wHotPEPt92.4 Distr:Limited Original:English
Motor Vehicle Air Pollution
Public Health Impact and Control Measures
Editedby David Mage and Olivier Zali
Division of EnvironmentalHealth EcotoxicologyService World HealthOrganization Departmentof PublicHealth Geneva,Switzedand Republicand Cantonof Geneva Geneva,Switzerland @ World HealthOrganization and ECOTOX ,lgg2
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Credits:cover photograph of Genevaby E.J. Aldag @.J. Press),Geneva; cover photographof Mexico City by ASL, Lausanne;stamp design, copyright Sweden PostStamps. MOTOR VEHICLE AIR POLLUTION
PTJBLICHEALTII IMPACT AND CONTROLMEASURES
Contents Page
Foreword- Wilfried Kreiseland Guy-OlivierSegond v
Executivesummary vii
1.Introduction.... 1
2. Review of the health effectsof motor vehicle traffic . 13
- Part I. Epidemiologicalstudies of the healtheffects of air pollutiondue to motorvehicles - IsabelleRomieu 13
- Part II. Effectson humansof environmentalnoise particutarly from road traffic - RagnarRylander 63
3. Humanexposure to motor vehicleair pollutants- PeterG. Flachsbart 85
4. Reviewof motor vehicleemission control mqNures andtheir effectiveness- Michael P. Walsh 115
5. Casestudies of motor vehiclepollution in cities aroundthe world - MichaelP. Walshand David T. Mage l3g
6. Casestudy of motor vehiclepollution and its controlin Geneva- FranqoisCupelin and Olivier Zali . . 173
7. Summaryand conclusions . . . 219
8. Appendices Fundingfor this reporthas been provided by the World HealthOrganization, the Departmentof Public Health of the Republic and Cantonof Geneva,and the Governmentof Norwav.
The editorswould like to thankthe following peoplefor their help in the review andpreparation of this document:
D. Calkins G. Ozolins N. Florio J. Rabinowitz A. Katz A. Rougemont T. Kjellstrdm A. Stroumza J.-Cl. Landry J. Somers
The Division of EnvironmentalHealth (EHE) of the World HealthOrganization (WHO) consistsof units for Preventionof EnvironmentalPollution @EP) and CommunityWater Supply and Sanitation(CWS) and it is closely allied with the Programmeon ChemicalSafety @CS). PEP is responsibleinter alia for the WHOruNEP GlobalEnvironment Monitoring System (GEMS) Air Pollution MonitoringNetwork (GEMS/Air),Water QualityMonitoring Network (GEMSAMater)and RadiationMonitoring Network (GERMON). The Programme for EnvironmentalHealth in Rural and Urban Developmentand Housing GUD), alsolocated in PEP, is responsiblefor the HealthyCities Programme.
The EcotoxicologyService @COTOX) belongs to the Departmentof Public Healft of the Republicand Canton of Geneva.It is the expertlaboratory for all environmentalconcerns in the area. Fifty peopleare working at ECOTOX. The fields of activity includeair (indoor,outdoor, industrial emissions controls, occupationalexposure), water (biological,bacteriological and physical-chemical controlsof lakes,rivers andswimming pools), soils andtoxic substancesanalysis, ecotoxicologicaltesting and environmental noise. ECOTOX is alsoinvolved in forensic analysis,in emergencyinterventions in casesof environmentalhazard and in evaluationof environmentalimpact assessments. FOREWORD
In almostall the large citiesof the world, air andnoise pollution from motor vehiclesare, or are fast becoming,major problems for the physicaland mental healthof the people. The industrializedcountries, where 86Vo of the world's vehiclesare to be found, havea long standingand extensiveexperience of the problem. In the developingcountries, rapid industrialgrowth andpopulation increasecoupled with rising standardsof living are likely to leadto patternsof motorizationthat resemblethose of the industrializedcountries. Sincethe 1960s, the world's motor vehiclefleet hasbeen growing faster than its population. The problemsare acutein certaincities in boththe developingand the industrialized world andunless controls are appliedor strengthenedimmediately, the damageto publichealth will becomevery serious.
The World HealttrOrganization (WHO) andthe UnitedNations Environment Programme(UNEP) have a long standingproject within the GlobalEnvironment MonitoringSystem (GEMS) to monitorthe air qualityof urbanareas of the world in this periodof rapid changeduring which nationsstrive to achievea sustainable economywithout degradation of the environment.
The Republicand Cantonof Genevain Switzerland,has developed a comprehensiveand sophisticatedair pollutioncontrol programme designed to meet SwissFederal air qualitystandards regarding pollutants derived from motor vehicleemissions.
In recognitionof ttre importanceof the problemof motor vehicleair pollution worldwide,WHO andthe EcotoxicologyService of the Departmentof Public Healthof Genevahave jointly producedthis reporton the globaltrends of motor vehicleair pollution, is effectson public healthand the availablecontrol measures.
Our report is intendedto provideessential information and encouragement to all countriesin their effortsto dealwith the problemscreated by the intense motorizationprocess. Casestudies (including an in-depthreport of the air pollutionmanagement plan of Geneva)are provided of the situationin various cities in developingand industrializedcountries and the motor vehicleemission controlstrategies that havebeen used or proposed. Throughthe sharingof experience,countries may be ableto avoidmistakes made in the past and introduceeffective measures in the nearfuture to reduceor limit damagettrat has already been incurred. Many countrieswill needto begin planningor applyingmore strictly, a progressivemotor vehicleemission control strategythat is feasibleand affordableand that will alleviatettre immediateair pollutionproblems.
This report is beingpublished to coincidewith the United NationsConference on Environmentand Development, Rio de Janeiro,June 1992, in supportof our commongoals of eliminatingthe impactsof environmentalhazards on the health of the peopleand attaining a stateof sustainabledevelopment for the future. We 'Think believethat if we all Globallyand Act Locally" our planetcan regain its healthand our environmentcan be saved.
Dr Wilfried Kreisel, Director, Guy-Olivier Minister, Division of EnvironmentalHeal&, Departmentof PublicHealth, World HealthOrganization, Geneva,Switzerland Geneva.Switzerland
vl EXECUTTVE SI]MMARY
This report addressesthe problemsof air pollutioncreated by the growth of motor vehicletraffic in the developedand developing countries of the world. The problemis viewedwittrin the contextof sustainabledevelopment in which the protectionof healthand of the environmentare priority concerns.The conclusionsand recommendations of this reportare intendedto provideguidance to countriesas they go throughvarious stages of development,in the formulation and implementationof soundpolicies to preventserious air pollutionproblems ftom occurringor worsening.
The reportbegins with a comprehensivereview of the healthproblems caused by motor vehiclepollution with referenceto the pollutantsozone, carbon monoxide, lead, nitrogendioxide, sulfur dioxideand suspendedparticulate matter. The secondpart of this chaptersovers the healtheffects of motor vehiclenoise. This is followedby a descriptionof how peopleare exposedto motor vehicleair pollutantsand an estimateof the numbersof peoplewho are exposedto them in traffic, alongsidebusy roadsand in residentialareas of high traffrc density. Motor vehiclecontrols are reviewedin termsof the effortsmade to reduceemissions (g/km) andto reducevehicle usage (km/yr).
Motor vehiclesare the major sourceof the following air pollutantsaffecting tle healthof populations:carbon monoxide (CO), nitrogendioxide (NOt, photochemicallyreactive hydrocarbons which reactwith NOr to form ozone(Or) and suspendedparticulate matter (SPM) which containslead @b).
At least90% of the carbonmonoxide in urbanenvironments comes from mobile sources.The high levelsfound in traffrc congestedareas (20 to 30 mg/m3)can leadto levelsof 3% carboxyhemoglobin(COHB) which produceadverse cardiovascularand neurobehavioral effects and seriously aggravate ttre conditionof individuaiswith ischemicheart disease.
Nitrogendioxide, the brownish-redgas responsible for the classicsmog haze of pollutedcities can cause respiratory problems in sensitiveindividuals, for example asthmaticsand young children. An extensivemeta-analysis of availablestudies
vll showsan approximate20% inqeasein risk of respiratoryillness for childrenwho havean increaseof 30 y.glm3exposure over a periodof weeks(e.g. children living in homesusing natural gas for cookingas comparedto childrenliving in homesusing electricity). Wherehigh annuallevels of NO, of the order of 100pglm3 are producedby motor vehicles,as in Los Angiles, this is a major causeof concern.
Ozoneis producedfrom the photochemicalreactions ofhydrocarbons and oxides of nitrogenwhich in urbanatmospheres are primarily of motorvehicle origin (60 - 80%). At levelsof ozoneof 200 - 400 pglnf , which fall abovethe WHO guidelinerange of 150- 200 pglm3for a l-hr average,people experience lung inflammation,decrements in pulmonaryfunction and decrease in resistanceto pulmonaryinfections. Areaswith high traffic densityand poor dispersionsuch as Los Angelesand Mexico City experience03 of the order of 600 - 7N pglrrif which seriouslydamages the healthof people,especially sensitive individuals. This is the major rqson why developingcountries must plan for emissioncontrols now, beforetheir developmentleads to similar conditions.
Suspendedparticulate matter (SPM), includingsulfuric acid aerosolis producedby the combustionof motor fuel, especiallydiesel fuel. Theseemission components are thought to be the main causeof the excessmortallty that was observedduring the Londonand New York smogepisodes ofthe 1950sand 1960s. These pollutantswere generatedfrom coal combustionso their chemicalconstituents are somewhatdifferent from thoseof motor vehicleSPM but it is believedthat the respirablefraction (PMro) of urbanSPM from non-coalcombustion processes will havesimilar effects. Motor vehiclesproduce a relativelysmaller proportion of SPM in the urbanenvironment than they do of CO andNO.. However,vehicle and urban SPM combinedare relatedto observedadverse health effects in the populationsexposed. Excess mortalrty for exposuresto thesepollutants is estimatedto be 1 in 10,000for currentlevels of PMls in Los Angeles,and the sameeffects may be expectedin metropolitanarqs of other countrieswith similar exposures.
Exposureto high levelsof motor vehiclepollutants occurs essentially in three situations:a) while insidevehicles (from the immediatelysurrounding traffic) b) while working in, or walkingalongside congested streets, and c) throughresidence in urbanneighborhoods with high motor vehicletraffic pollution (andfor ozone, in urban areasdownwind from the city center). Human exposurein these categoriesare reviewedand an estimateis madeof the numbersof peopleexposed in eachcategory. It is estimatedthat globally, 3.4 billion urbanvehicle trips are takendaily andthat at least 120million peoplespend a considerablepart of their working day in roadsidesettings (for examplestreet vendors and workers in shops fronting onto busystreets).
The controlmeasurqs necessary to containthe problemof largenumbers ofpeople beingexposed to high levelsof pollutantsare presentedand evaluated.With the viii economicdevelopment and motorization expected over the next decades,this problemwill becomeeven greater. The controlsdescribed are eithervehicle- based,to reducethe massof pollutantsper kilometerof travel G/km) or driver- based,to reducethe numberof kilometersof motor vehicletravel per day. The hardwarecontrols on emissions(catalyst, engine design, inspection and maintenanceetc.) are costlyand driver incentivesto re Casestudies of motorvehicle pollution in variouscities in the devclopingworld (Bangkok,Mmila, Mexico City, Surabayaand Taipei) and the developedworld (Los Angelesand Geneva)are presented.The traffic congestionand uncontrolled emissionsof developingcountries provide a markedcontrast to developed countrieswhere emission controls are mandatoryand funding is availablefor public transportsystems. Examples are provided of situationsin which the potentialfor seriousair pollutionepisodes is very greatand situationsin which uncontrolledgrowth of emissionsis taking place and where massivelyexpensive and controversialcontrols must be instdled in order to preventthese periodic episodes. A detailedreport of motor vehiclepollution and its controlin Genevais presented to providea broadoutline to authoritiesof the sortsof activitie.sthat mustbe consideredin order to evaluatetheir situation,estimate future growth anddevelop a stagedsequence of controlmeasures that are acceptableto the public and economicallyfeasible in the givensituation. The most importantfindings of the report are set out in the summaryand conclusions. It has been cleuly demonstratedthat motor vehicle air pollution can haveserious adverse health effects on the population. Theseproblems are likely to be particularlyacute in the rapidly growing citiesof the developingworld if uncontrolledgrowth of the vehiclefleet is allowedto takeplace. It is concluded ttratplanning must begin now to providefor alternativesto the motor vehicleand to reduceemissions of the vehiclefleets that the growingpopulations will demand as their economicstatus improves. It is hopedtlat this reportwill providea rationalbasis for administratorswho are responsiblefor air qualitymanagement planningto developappropriate control strategies as they striveto achievea state of sustainabledevelopment that doesnot adverselyaffect the healthof the people. lx Chapter1 INTR.ODUCTIONl In their effortsto achievesustainable development, politicians and administrators worldwideare facinga growingproblem of motor vehicletraffic emissionsand their effectson health. This book examinesthree aspects of the problemof air pollutioncaused by motor vehicletraffic: the effectsof traffic emissionson health,ways of limiting personal exposureto the emittedpollutants and ways of limiting the emissionsthemselves.' Only thoseissues relating directly to motor vehiclesare consideredhere. Those that are indirectlylinked are not discussed,most notably, the contributionof motor vehiclesto globalCO2 production, the relatedgreenhouse effect, the role of infrastructure(road network construction and design) and land useplanning. A brief bibliographyon the more generalaspects of air pollutionhas been prepared for the interestedreader and is to be found at the endof this chapter. Noisefrom motor vehicles,in termsof its effectson health,is consideredbut engineeringcontrols to limit this form of pollutioniue not. Traffic accidents, which representa seriouspublic healthproblem are alsobeyond the scopeof this report. It shouldbe notedhowever, that constraintson the numberof vehicleson the road will improveroad safetyand reduce the rate of trafftc accidentsin additionto reducingair pollution. The purposeof this report is to providea basisfor informeddecision making on how to controlautomotive air pollutionin both developingand developed countries. The importanceof contextis emphasizedthroughout and descriptions of the situationin a varietyof citiesof widely differentcharacter, are provided. Where we stand today Acrossthe entireglobe, motor vehicleusage has increased tremendously. In 1950,there were about53 million carson the world's roads;only four decades I The editors thank Michael P. Walsh for his assistanceon this chap0er. 2 A complementarydocument for the use of this material in training courses at university and pre-universitylevels is under preparationand will be publishedin 1993. Motor vehicleair pollution later, t}te globalautomobile fleet is over 430 million, more than an eight-fold increase.on average,the fleet hasgrown by about9.5 million automobilesper year over this period. Simultaneously,as illustratedin Figure 1, the truck and bus fleet hasbeen growing by about3.6 million vehiclesper year (Motor Vehicle Manufacturers'Association of the UnitedStates, Inc., 1991). While the growth rate hasslowed in the highly industrializedcountries, population growth and increasedurbanization and industrializationare acceleratingthe useof motor vehicleselsewhere. If the approximately100 million two-wheeledvehiclqs around the wodd are includedfurowing at about4 million vehiclesper yearover the past decade),the globalmotor fleet is now approximately675 million. As Figure 2 shows,the growthof motorizationexceeds the growthof population. Looking at the globalvehicle population today, it is clearthat thereare wide disparitiesbetween regions of the world andvehicle modes. Figure 3 showsthe distributionof the vehiclepopulation in variousregions of the world. Seventy- threepercent of the world's vehiclesare to be found in the OECD (organization for EconomicCooperation and Development) countries. In the poorestcountries of the world where57 % of the world's populationlive, are to be found only 1.7% of the world's vehicles. Most of the world's peoplestill live and work largely without motorizedtransport. Table 1 showsthe enormousvariation in motorizationbetween countries and regions,ranging from lessthan 1 to more than600 vehiclesper 1000inhabitants. If the developingcountries reach rates of ownershipcomparable to thosefor Europeand NorttrAmerica now, the problemsrelated to massiveconcentrations of populationin urbanareas will be greatlyexacerbated. Comprehensivedata are not availableon air pollutionemissions from transportationand other activities,for all countries. For the twenty-fourOECD countries,however, available data shows that motor vehiclesare the main source of emissionsof carbonmonoxide (co), oxidesof nitrogen(No), andvolatile organiccompounds Crable 2). ln urbanareas where pollution levels tend to be highest,the motor vehiclecontribution tends to be evenhigher. Usually,over 90% of the co in city centerscomes from vehiclesand it is cornmonto find 50 to 60% of the hydrocarbons(HC) and NO, comingfrom this source. Future trends in motor vehicleregistrations and emissions As illustratedin Figure2, worldwide,the numberof motor vehiclesis growing far fasterthan the globalpopulation - 5.2Voper yearbetween 1960 and 1989, comparedto 2.r% per year, respectively.Analysis of the trendsin globalmotor 2 Introduction vehicleregistrations reveals that the globalfleet hasbeen growing linearly since before 1970and that eachyear for two decadesan additional16 million motor vehicles,not includingtwo-wheeled vehicles, have been added to the world fleet. Worldwideregistrations have been growing by about1.8 carsper 1000persons or 2.3 vehicles(cars plus trucksand buses) per 1000persons (Figure 4) Motorcycles per capitaover the last decadehave been stable. If this trend wereto continue until 2010, therewould be 154motor vehiclesper 1000persons (excluding motorcycles)compared with 112 in 1990. As illustratedin Figure5, per capita vehiclegrowth is universalalthough still overwhelminglydominated by the OECD countries. The contributionof Africa andlarge areas of Asia to this growth is minimal, althoughair pollutionfrom motor vehiclesis alreadya problemin the large citiesof theseregions, where the per capitavehicle growth is concentrated. Projectionsof the future vehiclepopulation have been made, taking into account populationgrowth and economicdevelopment, which arethe major factors influencingvehicle growth. Estimatesof cars,trucks and buses, and motorcycles for the next forty yqus are summarizedin Figure6. In makingthese estimates, it was assumedthat vehiclesaturation, increased congestion and increasingpolicy interventionsby governmentswould restrainfuture growth, especiallyin highly industrializedareas. In spiteof thesefactors, vehicles per capitaare estimatedto rise in all areasof the world. It shouldbe emphasizedthat withoutpolicy interventions,the growth is likely to be muchhigher. As notedearlier, the globalvehicle fleet hastended to be dominatedby the highly industrializedareas of North Americaand Western Europe. This patternis graduallychanging not becausethese areas have stopped growing but because growth ratesare acceleratingin other areas. By early next century,based on currenttrends, the rapidly developingareas of the world (especiallyAsia, Eastern Europeand Latin America)and the OECD Pacificregion will haveas many vehiclesas North Americaand Western Europe (Figure 7) althoughper capita rateswill remainsubstantially lower. Decisionshave to be takenconcerning land-use planning, mass transit construction andfuel characteristics.These choices will stronglyinfluence development over the next 20 to 50 years. In orderto minimizefuture costsin termsof healthand clean-up,solutions to air pollutionproblems need to be found and implemented immediately.We hopethe informationcontained in this reportwill contributeto thesevital initiatives. 066r 086r. 016r 096r o nq 6o YcrtnEe q u\b t .9 !l cE g zFo a (Dbo ilililtil E H o o o a ilt,h | 'o U'UI C o k A fh o k bn o ncAr q vt u I .9o ooooooo =o oooooo =r\ (oro POPUIATION(1,(x)O,000,0oO) VEHTCLES{1(x),mo,O(x)l + CARS + TRUCKS& BUs$ -X- MOTOFCYCLES + POPULANON 1 0 Figure2. Historicaltrends in vehiclesand population. E nesror THE 1"*"---r Figure3. 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Motor vehicleshare of OECDpollutant emissions (1000 tons, 1980). Source : OECD EnvironmentalData, Organizationfor EconomicCooperation and Developement,Paris, 1987. REFEREI\CES Motor VehiclesManufacturers' Association of the UnitedStates, Inc. WorldMotor VehiclesData, 1991edition. InternationalRoad Federation. World Road Staistics1986-190. Geneva/lVashingtonD.C., 1991. Organizationfor EconomicCooperation and Development. OECD Environnuntal Data. Puis. 1987- t1 Motor vehicle air pollution BIBLIOGRAPHY Barde, J.-P. and Butlon, K. (Eds) Transportpoliq and the enviromvnt. Six casestudies. EarthscanPublications Ltd., London(1990). Cohn, F. and McVoy G.R. Envirownentalanalysis of transponaion sysrcms. Wiley-InterscienceNew York (1982). ECMT. Transpoftgrowh in question. l2th InternationalSymposium on Theory andPractice in TransportEconomics. Sub-Topic 5 Environment,Global and Local Effects. (3 papers),Lisbon @4May 1992). Faiz, A. et al. Automativeair pollwion: issucsand optionsfor developing countries. WPS 492, World Bank, WashingtonDC (August1990). Kageson,P. Internalising social costsof transporl. preliminary Study. The EuropeanFederation For Transportand Environment(January 1992). Kumares,s. et al. Environmcntaland ecologicatconsiderabns in land transport: a resourceguide. world Bank, Policy Planningand Researchstaff, Infrastructure andUrban Development Department Report INU41 (March, 1989). NSIEM. Health risls resultinglrom exposureto motor vehicle exhaust. National SwedishInstitute of EnvironmentalMedicine, Stockholm (1983). PublicHealth Alliance. Healthon thc move. policiesfor Healthpromoting Jransport. The Policy statementof rhe Transportand Health study Group, London(1989). Rijkeboer, R.c. Technologiesfor controlling emissionsof air poilwants from mobilesources. UNRCE, Brussels(1989). WHO. Our planet our health. Report of the World Health Organization Commissionon Healthand Environment, Geneva (1992). wHo. Potential health effeas of climatic change. Report of a world Health OrganizationTask Group,WHOiPEP/90.10, Geneva (1990). t2 Chapter2 Part I EPIDEIVIOLOGICAL STT]DIESOF THE HEALTH EFTT,CTS OF AIR FOLLUTION DTIE TO MOTOR VEHICLES IsabelleRomieu' Introduction Severalmajor classesof air pollutantshave the potentialto affectthe healthof populations(ATS, 1978). Thesepollutants result either ftom primary emissions or atmospherictransformation. Motor vehiclesare the major sourceof a number of thesepollutants, in particularcarbon monoxide, nitrogen oxides, unburnt hydrocarbons,ozone and other photochemical oxidants and leadand, in smaller proportions,total suspendedparticulate, sulfur dioxideand volatile organic compounds(t{EI, 1988). With growingurbanization and vehicle densrty, and the greatexpense of pollutioncontrol, urban air pollutionhas become a crucial problem and it is now urgent to undertakerisk assessmentsin order to evaluate andprioritize controlstrategies. In this chapter,the epidemiologicalevidence of the healtheffects of pollutantsthat havea direct or indirectsource relationship to automotiveemissions is reviewed. Individualsexposed to a high concentrationof air pollutionresulting from roadtraffic are at the sametime exposedto high noise levels;the healtheffects of the latter will be discussedin Part II. IsabelleRomieu, M.D., Dr.Sc. MedicalEpidemiologist, World Health Organization,Mexico City, Mexico. 13 Motor vehicleair pollution Factors conditioning the toxic effect of pollutants Motor vehicleexhaust is a complexmixture, the compositionof which dependson the fuel, type andoperating condition of the engineand the useof any emission controldevice. Pollutantsand their derivativescan cause adverse health effects by interactingwittr, and impairing,molecules crucial to the biochemicalor physiologicalprocesses of the humanbody. Threefactors condition the risk of toxic injury from thesesubstances: their chemicaland physical properties, the dose of the materialthat reachescritical tissuesites, and the responsivenessof these sitesto the substance.The physicalform andproperties (e.g. solubility)of airbornecontaminants will influencetheir distributionboth in the atmosphereand in biologicaltissues, and therefore the dosedelivered to the target-site.This dose is very difficult to determinein epidemiologicalstudies and therefore surrogate measurementsare used ranging from atmosphericconcentration to dose determinationin blood or more accessiblebody tissues(for example,hair). For somepollutants, mathematical models of the relationshipbetween exposure and dosecan alsobe usedto developsurrogate mqnures. The interactionof pollutants with biologicalmolecules (or receptors)triggers the mechanismof toxic response that may act by direct stimulationor by a cascadeof molecularand cellularevents that ultimatelydamage tissue (HEI, 1988). The differentpathways from pollutant sourses,from exposurethrough inhalation to toxic effectsare shownin Figure 1. Pollutantseffects may alsovary acrosspopulation groups; in particular,the young andthe elderlymay be especiallysusceptible to deleteriouseffect; persons with asthmaor other preexistingrespiratory or cardiacdiseases may experience aggravatedsymptoms upon exposure (HEI, 1988). Health effects of specific pollutants Substancesmainly affecting the airways Amongthe extremelylarge number of substancesin the exhaustof motor vehicles, severalexert irritant inflammatoryeffects on the respiratoryorgans. The main onesare nitrogenoxides, ozone and other photochemical oxidants, as well as sulfur oxidesand particulate matter. Nitrogen oxides Nitrogendioxide (NO) is an irritatinggas that is absorbedinto the mucosaof the respiratorytract. Upon inhalation80-90% of NO2can be absorbed,although this proportionvaries according to nasalor oral breathing. The maximaldose to the lung tissueis at the junction of the conductingairway andthe gasexchange region. BecauseNO2 is not very solublein aqueoussurfaces, the upperairways l4 Health effects of air pollution Figure1. Pathwaystfrom pollutant sources to toxiceffects. Fuel Engine characteristics Emission controls GENETICAND Doseto ENVIRONMENTAL pulmonarytissues MODIFIERS Cellularand molecularcascade o; s . Onlyexposure through inhalation isshown. Source:HEl.19BB 15 Motor vehicle air pollution retainonly small amountsof inhalednitrogen ox-ides. Nitric and nitrousacids or their saltscan be observedin the blood andurine after exposureto Nq (WHO, 1987a). Levelsof exposureto nirogen dioxidethat shouldnot be exceeded(WHO guidelinaslevels) are respectively4gg p,gtrr31O.Zt patrs per million [ppm]) for t- hour and 150pglm3 (0.08 ppm) for 24-hours(WHO, 1987a). In certainoccupations, workers are intermittentlyexposed to high concentrations of oxidesof nitrogen,particularly No and No2. The spectrumof pathological effectsin the lung resultingfrom occupationalexposure to nitrogenoxides range from mild inflammatoryresponse in the mucosaof the tracheobronchialtree at low concentrations,to bronchitis,bronchopneumonia, and acute pulmonary oedemaat high concentrations(WHO, 1977). Most of the epidemiologicalresearch studies at the communitylevel havefocused on the acuteeffects of shortterm exposureto high levelsof Ne, andthere are few dataon long term effectsof low-levelor repeatedexposure at peaklevels. Morrow (1984)has shown that No, canbe toxic in certainbiological systems, and acuteexposure to No2 has beenreported to affect both the cellular and humoral immunesystems. other authors@amji andRichters, 1989) have reported a reductionof r-lymphocytesubpopulations following acuteexposure to Ne, which may reflect a functionalimpairment of the immuneresponse. Therehave been numerous controlled studies of the effectof nitrogendioxide on the lung functionsof healthyindividuals, as well as asthmaticsand subjects with chronicbronchitis @PA, 1982a). Shortexposure (10-15 minutes) to concentration of No2 exceeding1300 pglm3 (0.7 ppm) causedfunctional changes in healthy subjects,particularly an increasedairway resistance. Recent controlled studies show conflicting results concerningrespiratory effects in asthmaticsand healthy individualsat nitrogendioxide concentration in the rangeof 190-7250pglm3 10.t- 4.0 ppm). The lowestobserved level to affectlung functionconsistently was a 30-minuteexposure with intermittentexercise, to a nitrogendioxide concentration pglm3 (0.: 9f 560 ppm). Asthmaricsappear to be moreiesponsiveto Ne and their lung functionsmay be affectedby a level of 940 pglm3 (0.5 ppm). Nitrogen dioxidealso increases reactivity to pharmacologicalbronchoconstrictor agents and a greaterresponse to theseagents is observedin asthmatics(WHO, 1997a). Few communityepidemiological studies of outdoorNO. exposurehave demonstratedan associationbetween ambient air levelsof No* compoundsand measurablehealth effects. However,methodological problems, such as presence of mixtureof pollutants,lack of controlfor parentalsmoking or indoorsources of No2 (speizeret al., 1980),with all of the studiespreclude acceptance of any of 16 Health effects of air pollution the resultsas clearevidence for increasein acuterespiratory illness due to NO* exposures.These studies have been extensively reviewed (EPA, 1982). More recent studieshave taken the opportunity of comparinggroups exposedto NQ emittedfrom the combustionof gasinside buildings. Speizeret al. (1980) investigatedthe effectof indoor NQ concentrationdue to gas-stoveuse and reportedan averagerate differencebetween exposed and non-exposedchildren of 32.5 per 1000children for respiratoryinfection before age two. Theseresults were not confirmed by other studieswhich could not find a significant effect of the useof gas-combustionappliances (WHO, 198?a). Sametand Utell (1990) havepointed out the limitationsof theseepidemiological studies. Anotherstudy conductedamong school children aged 7 to ll yearsin six US citiesover a 5 year period (1983-1938)showed that a 28.6 pglm3 10.0t5ppm) increasein the householdannual NO2 meanwas associatedwith an increasedcumulative incidenceof lower respiratorysymptoms [odds ratio (OR;= 1.4; 95Voconfidence interval(C1) 1.1-1.71.There was no consistenteffect of NQ on pulmonary functionmeasuremen8 (Neas et al., 1991). A meta-analysisof 11 epidemiological studiesgiving quantitativeestimates of effectsshowed increases of respiratory illnessin childrenof lessthan 12 yearsof age,associated with long-termexposure to high concentrationsof NQ (gasstoves) compared to childrenexposed to low concentrationsof this pollutant:a differencein exposureof 30 pglmr resultingin an increaseof about20% in the oddsof respiratoryillness (odds ratio 1.2; 95% confidencelimis:1.1-1.3). This becomesa publichealth concern since recurrent childhoodrespiratory illnass may be a risk factor for later susceptibilityto damagedlungs. Thereis howeverinsuffrcient epidemiological evidence to draw any conclusionregarding the short-or long-termeffects of NQ on pulmonary function (Hasselbladet al., 1992). In summary,in spiteof decadesof laboratory,clinical and epidemiological research,tle humanhealth effects of NQ exposurehave not beenfully characterized.The toxicologicalevidence has indicated hypotheses to be testedin humanpopulations (table 1) but limitationsof the clinical and epidemiological studieshave precluded definitive testing ofthese hypotheses(Samet et al., 1990). Ozoneand other photochemicaloxidants The primary targetorgan for 03 is the lung. 03 exposureproduces cellular and structural changes,the overall effect of which is a decreasein the ability of the lung to perform normalfunctions. Ciliatedand Type 1 cells are the mostsensitive to ozoneexposure (ciliated cells function to clearthe airwayof inhaledforeign material). Proliferationof non-ciliatedbronchiolar and type 2 alveolarcells occursas a resultof damageand death of ciliatedand type I cells. The lung airspacelocation where ozone exposures cause a major lesionis the centriacinar area,which includesthe endof the terminalbronchioles and the first few 17 Motor vehicleair pollution Table 1. Potentialhuman health effects of NO2 Health Effect Mechanism Increasedincidence of respiratory infections Reducedeffrcacy oflung defenses Increasedseverity of respiratory infections Reducedefficacy of lung defenses Respiratory symptoms Airways injury Reducedlung function Airways and alveolar (?) injury Worsening of tle clinical statusof personswith asthma, chronic obstructive pulmonary diseaseor other chronic respiratory conditions Airways injury Source:Samet and Utell, l99O generationsof eitherrespiratory bronchioles or alveolarducts (depending on the species)(Lippmann, 1989a). Thus effrciencyof gasexchange can be compromisedin the affectedarea. Levelsof exposurethat shouldnot be exceeded (WHO guideline)are 150-200pglm3 (0.076{.1 ppm) for t-hour exposure,and 100-120pglm3 (0.054.06 ppm) for an 8-houre*posure (WHO, lgSlb). The observedhealth effects ofphotochemical oxidants exposure cannot be attributedonly to oxidantsbecause photochemical smog typically consistsof e, No2, acid sulfateand other reactiveagents. Thesepollutants may haveadditive or synergisticeffects on humanhealth, but ozoneappears to be the most biologicallyactive (WHO, 1987b). Most of the studieson the healtheffects of e havefocused on short-term(1-2 hour) exposureand have indicateda numberof acuteeffects of 03 and other photochemicaloxidants (rable 2). This literaturehas been extensively reviewed (EPA, 1986). studiesof hospitaladmissions in relationto e exposurereported an increasein hospital-admissionrates for respiratorydiseases @ates and Sitzo, 1983)and asthmaattacls (whittemoreand Korn, 1980;white and Etzel, 1991). However,due to methodologicallimitations, these studies cannot demonstrate an associationbetween ozone exposure and respiratory illness. Different authors haveinvestigated symptoms related to 03 exposure.In a clinical study,Avol et (1987) al. studiedthe occurrenceof symptomsin subjecsexposed to e 18 Health effects of air pollution Table 2. Humanresponse to single Q exposure Response Subjects Exoosureconditions t10t Ms de@6t ia FEB hd.lthy yohg md l8O ppb with inEmiu.nt hevy Gl@iro for 2 br€3 in puif&d tir 100 ppb vith mo&e *rcirc for 6.6 hro3 in purified .n 100 ppb with vcry hqvy cHi.o fo. 0.5hro, in mbid rir helthy childm 100 ppb-&od iumcr mp ppgnnq in rs$imt.ir Is€&d@ugh belhy youag mcn f20 ppb with inEmittat bqvy @i6€ ior 2 br43 itr purficd .ir helthy you8 run tO ppb modc* crcrcirc for 6,6 tuO! ir pu.ifcd .ir hellhy yout m6 ud wmcn l2Ol30 ppb hovy Gi@irc foi 162t Ein€! in puritrcd air Rcducod ethlaio pcforrc helthy young md IEO ppb with creisc d VE of 54 Umin for 30 nin, 120 Umia for 30 mh43 ia purifiod rir h€8lthy youg M rnd sm6 l2Gl30 ppb with creLo.t VE of 3G12O Umb fo. 1628 mh43 in puri.fiod eir lloE&d siMy nsrivity helthy youg tM 80 ppb wilh modcntc q@ire for 6.5 brO3 i! pu.ifiod rir halhy yosg .duL tM with 180 ppb with lF.yy Miro for 2 hr43 in purifed rir lllcrgi: fiinitit IlcMod riMy pmcrbility hc.lthy yowS m6 aOOppb with intomit&'t hc.W ffiirc tor 2 hlO3 itr purifcd rn tacurodeimy intlmutio helthy youtrt M 80 ppb with mo&rE rerci& tor 6.6 brOr h purificd rir Aoc.hcr.d tdrhaborcbid Fnbb heltb), youog m 200 ppb wid| int mitht lighl *rciio for 2 hrOt in d@ purificd rir 'lppb = 2pgtf Source:Lippmann, 1989b level rangingfrom 0 to 640 pglfir3. Symptomswere classifiedas upper respiratory(nasal congestion or dischargeand throat irritation), lower respiratory (substernalirritation, cough,sputum production, dyspnea, wheeze and chest tightness)and non-respiratorysymptoms (headache, fatigue and eye irritation). Scoreswere then calculated, based on the intensityof the symptomspresented. Resultsshowed a dose-responserelationship between effective dose of Or (O: concentration. time . ventilationrate) and symptomscores (Figure 2). Imai et al. (1985)reported significant symptom increase in adultsduring periodsof increasedambient 03 exposurein Japan. Ostroet al. (1988)analyzing data collectedfor 6 years(National Health Interview Survey, 1976-1981) showed that ambient03 levelswere associatedwith restricteddays of activity dueto respiratoryillness in the working population. It canbe derivedfrom this analysis t9 Motor vehicle air pollution Figure2. Effectof ozoneon respiratorysymptoms. 100 u o UpperRespiratory Symptoms r NonRespiralory Symptoms o5so o a LowerRsspiratorySymptoms >80 F 970 2"o Hso 8+o fl.0 F s20 8ro d E 0L 0 1000 2000 3000 4000 EFFECTIVE03 DOSE (micrograms delivered in 2 hr) Keinmanet al, 1989 that the changein the numberof an individual'sminor restrictedactivity dayson a givenday (i) for a givenpopulation (i) (MRADJ;) is equalto the changein the daily high 03 hour in ppm on a given day (dOi), multipliedby the population exposed(APOP), multipliedby a coefficient(0.077 assuming an averagenumber of minor restricted = . activitydays in a yearof 7.8 days[dMRADij 0.077 dOii- 'APOPT) (Kleinman,1989). In sum, effectswhich havebeen iissociated with hourly iverageoxidant levels beginning at about200 pgtnf (0.10 ppm) include: eye, noseand throat irritation, cough,throat dryness, thoracic pain, increased mucousproduction, rales, chest tightness, substernal pain, lassitude,malaise and nausea. Ozonelike NO2 caninduce increased non-specific airway sensitivity to inhalation challengetesting with bronchoconstrictiveagents (HEI, 1988). Recentresearch has shownthat effects can be producedby exposuresas short as 5 minutes, and that variouseffects become progressively larger as exposuresat a given concentrationare extendedin time up to 6.6 hours. However,repeated exposures to a given concentration(6.6 hoursto 0.08, 0.10 and0.12 ppm) on several consecutivedays result in attenuationof functional changesbut persistenceof airwayhyperresponsiveness. This suggestsongoing action of 03 on the lung (Folinsbee,1991). Althoughsmokers and subjectswith preexistingpulmonary diseasedo not appearto be more sensitivethan othersto Q, within the apparently normalpopulation there is a rangeof responsivenessto 03 that is reproducible (wHo, 1987b). 20 Health effects of air pollution The inhalationof 03 causesconcentrationdependent decreases in the averagelung volumesand flow ratesduring expiratory manoeuvre,and meandecrements increasewith increasingdepth of breathing(Lippmann, 1989a). Decreasein lung functionsin healthychildren and youngadults have been_ reported at hourly average03 concenlrationsin the rangeof 160-300pglm3 10.084.150 ppm) (see Table3). Basedon estimatesfrom Spektoret al. (1988)moderate physical activity for a rangeof exposurefrom 38 to 226 pglm3(0.019 to 0. 113 PPq) for I hour couldlead to a decrementof 0.5 ml/pglm3for FVC1 and0.7 ml/pglm3for FEV12;this would result in a decrementof 180 ml for FVC and 250 ml for FEVI for a concentrationof 400 pglm3 (0.2 ppm) 03 (l-hour average).From these data,average decrement in FVC, FEVI andPEFR3 of 4.9%,7.7Voand 17% respectiveltwere predicted for the curientEPA standardfor 03 2aOFgtnf (0.12ppm). In a studyconducted in Mexico City amongschool children, Castillejos et al. (1991)reported an acuteand subacute effect of 03 on lung functions. However the decrementswere smallerthan that expectedfrom the regressionslope of Spektoret al. (0.8% for FVC and0.8% for FEVI with a ma:rimum03 level of 2a0 y"glnr3(0.12 ppm) at 24 hoursprior !o testing. The mean03 exposure48 hoursand 168hours (7 days)were the more significantin predictingFEVI and FEF2s-?s4.These authors suggest that childrenchronically exposed to O, may presenta phenomenonof "tolerance". This finding is in agreementwith the fact that repetitiveexposures tend to produceless of a response(Ilackrcy, 19771, Folinsbee,1991). Thepotentialadverseeffectofsuch "tolerance" isnotknown. Asthmaticsare not more sensitiveto 03 as shownby their FEVI response, however03 may exacerbatethis diseaseby facilitatingthe entry of allergensor becauseof the inflammationit induces. Thereis someevidence that 03 may act synergisticallywith other pollutants,such as sulfate and NOr (Kleinman, 1990). Koenig et al. (1989)showed that inhalinglow concentrationof 03 may potentiate the bronchialhyperresponsiveness of people with asthma!o sulfur dioxide exposure. I FVC= ForcedVital Capacity 2 FEV, = ForcedExpiratory Volume in one second 3 PEFR= PeakExpiratory Flow Rate a FEFrr-rr= ForcedExpiratory Flow from 25% to 75Voof theForcedVital Capacity a7 LL Motor vehicle air pollution Table3. Meanfunctional changes per ppb* 03 in aduttsand children after exercise. Comparison of- resultsftom field andchamber exposure studies with q. Expo{F M6 nb of frstioill ch.iuc . No. of Activity lcvcl (oxcrciF) o, gDJ@! | (oitr.Y?d.) titr FVC FEVr PEFR FEFUS Ssdy A8c nltc (do) (PPb) &od!r 0ibn) (nyppb) (ouppb) (oUdppb) (0Urppb) ADULTS Foli!$edd t988 l0M tE-33 Modcn& 3e5 O00) t2ff -3.t 4.5 -5.0 (40) Gibbo0 & A&o 1984 t0F n.91.2.5' Hi8h 50 (60) r50a -t.l -t.0 {.6 (55) AYol d d 1984 42M,tF 26.4*6.9' High 60 (60) l53b -1.2 -t.3 -1.5 -t.5 (57) l60t McDo@|l 4 d I9t3 DM 22.3x3.t' High r20 (60) r2ff J.4 -1.3 -2,9 (65) 20M B.3ri.2' Hi8h 120(60) -l.t -1.6 -3.0 l80a (65) Kull6 ct .l l9tj 20M 25.3*1.t' HiSh r20 (60) 4.5 4.2 -2.1 (6r) l50t Liu 4 d 1986 24M l8-33 HiSh 120(60) 4.1 {.6 -l.l -t.l (6r) l60t Spoth d d l98t 20M, l0F 2214 Vricd 29.3*9,2' -1.,f -9.2 {.0 or.6134.o il-l-j,.4b 7M,3F 22-$ (64.5*10.o 26.7xt.f -3.0 -t3.1 -9.7 2t-t240 CHII-DR.EN Lioy d d l9t5 l7 M,22F Iaw 15G550 {.1 {.3 -3.0 4.6 }Ul45b Kimcy ct d 1988 94M,60F tut2 I.w 1440 4.9 .1.0p 1.9 7-78b Lippum d .l 1983 34M,24 F t-13 ModcdE 15G550 4.t ,16-llob Spckor ct d 53M,38F Modcntc 15G550 -t.0 -1.,1 {.t -2.5 l9-ll3b Avol c d 1988 33M,33F E-tt Modcnta 60 (60) 4.3 4.4 Q2) ll3b Avol .t .l 1985 il6 M, 13F t2-t5 High 60 (60) -0.E -t.6 4.7 Q2) l5oa MoDo@[ ct d 1965 23M t-ll Vcry High 150(60) -0.3 {.5 -tt 4.6 oe) 12cE 'Mean * S.D r Ozone concentration within purified air. b Ozone concentration within ambient mixturs. o FEV0.75 +1ppb=2p.ghf Source: Lippmann, 1989a 22 Healtheffects of air pollution Experimentalstudies in animalsand humans have shown that O, increasesairway permeabilityand particle clearance, causes airway inflammationand decreases in bactericidalcapacity, as well as structurealteration in the lung (Lippmann, 1989b). It is not yet knownwhether repetitive inflammation has long term consequences. The long-termexposure effects of O, are still unclear,but thereis goodreason for concernthat repeatedinsults could lead to chronicimpairment of lung developmentand functions. Animal studieshave demonstrated progressive epithelialdamage and inflammatorychanges that appearto be cumulativeand persistent,even in animalsthat haveadapted to exposurein termsof respiratory mechanics(fepper et al., 1987),at concentrationsslightly higherthan those that produceeffects in humans. Furthermore,for somechronic effects, intermittent exposures(i.e. alternatemonths) can produce greater effects than those produced by continuousexposure regimes (all periods)to the sameatmosphere that resultin a higher cumulativeexposure. These results suggest that diseasepathogenesis dependson the effectsproduced by lung defensiveresponses to the direct damage to epithelialcells causedby O:, as well as on the direct effectsthemselves (Lippmann,1989a). Epidemiologicalstudies on populationsliving in Southern Californiasuggest that chronicoxidant exposures affect baseline respiratory function. Comparingtwo communitiesfrom this area,Detels et al. (1987)found that baselinelung functionswere lower andthat therewas a greaterrate of decline in lung functionover 5 yearsin the high oxidantcommunity. Howeverthis study hasbeen criticized for severalpitfall (poor exposuremeasurements, lack of adjustmentfor potentialconfounding factors such as indoorair pollution,and occupationalexposure). Similarly, Kilburn et al. (submitted,1991) compared the lung functionsof 1,093Los Angelesschool children and 1,805Houston school childrenin the secondand fifth grades. Los Angeleschildren had 6% Lower baselinevalues for FEVI and 15% lower FEF25_zs.Aerosol administration of metaproterenolto Los Angeleschildren improved FEVI by l% andFEF25_75 by 6.6%, but expiratoryflows were still below Houstonchildren's values, suggesting that impairmentwas not reversible. Repeatedmeasurements of lung functions among106 Mexican-American Los Angeleschildren showed that FEV, was 2.0 percentlower thanthe predictedvalue and FEF25-?' was 7.0 percentlower than the predictedvalue in 1987compared to 1984. FVC remainedunchanged. The authorsconcluded that the worseningof airwaysobstruction in thesechildren is probablydue to air pollution(Kilburn, submitted 1991). Euler et al. (1988)evaluated the risk of chronicobstructive pulmonary disease due to long-termexposure to ambientlevels of total oxidantsand NQ in a cohortof 7445Seventh Day Adventistsnon-smokers, who had both residedin Californiafor at least 11 years,and were agedat least25. The resultssuggest a significant associationbetween chronic symptoms and total oxidans above200 pglm3 23 Motor vehicle air pollution (0.10 ppm). Howeverwhen cumulative exposure to TSP was enteredin the model,only TSP exposureabove 200 pglm3showed statistical significance. Sherwinet al. (1990)conducted an autopsystudy among 107 young non-smoker aduls aged14 to 25 years,who died of non-respiratorytraumatic causes in Los Angelescounty. They found that 29 of themhad lungswith severerespiratory bronchiolitis,of the kind first describedin youngsmokers (Niewohner et al., 1974). Moderatechanges were present in a further 51 cases. This datamay be the first to showthat current03 exposuresare causingthe samelesions ttrat have beenobserved in monkeysexposed to Q @ustiset al., 1981). In summary,the transienteffects of 03 seemto be more closelyrelated to cumulativedaily exposurethan to onehour peakconcentrations. Several studies providedsufficient information to allow a quantitativeevaluation of the potential impactof shortterm exposureto 03 on populationsubgroups. Kleinman et al. (1989)summarizing data from differentstudies derived a dose-response relationshipbetween change in FEVI andeffective dose of 03 @roductof concentrationof 03 . time . ventilationrate) (Figure3). Theseauthors also calculateddose-response functions to determinethe changein the percentageof the populationaffected by specificsymptoms according to 03 ambientlevel. The modelfitted well dataderived from clinical studies. Finally, the work of Ostro et al. (1988)can be usedto determinethe changein restrictedactivity days associatedwith changesin ambient03. Howeverthese models can only provide an approximationsince the effectsof O, may be potentiatedby the presenceof other environmentalvariables such as acid aerosols. The effectsof long term chronicexposure to O, remainpoorly defined,but recent epidemiologicaland animalinhalation studies suggest that currentambient levels (closeto 240 pglm3or 0.12 ppm) are suffrcientto causepremature lung aging (Lippmann,1989b). More researchis neededon the chroniceffects of 03 on lung structure,disease pathogenesis and interactionwith other environmentalfactors. Sulfur Dioxide and Paniculate Matter Sulfur dioxideand particulate matter represent only a minimalpart of automotiveemission, however, these pollutants react and may havea synergisticeffect with otherpollutants emitted by vehicles. Thereforethe discussionin this sectionis limited to the mostimportant points. Inhaledsulfur dioxideis highly solublein aqueoussurfaces of the respiratory tract. It is thereforeabsorbed in the noseand the upperairways where it exertsits irritant effectas well; little of it reachesthe lungs. In additionto irritation of the upperairways, high concentrationscan cause laryngotracheal and pulmonary oedema.From the respiratorytract, sulfur dioxideenters the blood. Elimination 24 Health effects of air pollution Figure3. Effectof ozoneon pulmonaryfunction. a 0.1ppm r 0.2ppm o 0.3ppm o 0.4ppm 15 s LeastSquares Fit - tJ.t u- 10 z tJl z I <)5 o 3 0 500 1000 1500 2oo0 2so0 3ooo 3500 4ooo 4500 5000 EFFECTIVEOZONE DOSE (micrograms) Source:Kleinman et al. 1989 occursmostly by the urinary route (afterbiotransformation to sulfatein the liver). The depositionof particulatematter depends mainly on the breathingpattern and the particlesize. Largerparticles are mainly depositedin the extrathoracicpart of tlre respiratorytract (> 10 pm) and mostof the particles5-10 pm arc depositedin proximity to the fine airwayswith normalnasal breathing. With mouthbreathing the proportionof tracheobronchialand pulmonary deposition increases (WHO, 1987c). Ambientlevels of sulfur dioxideand particulate matter that shouldnot be exceeded(uS- EPA guidelineslevels) are respectively80 pglm3 (0.03 ppm) for annualaverage and 365 pglnf (0.14 ppm) for 24-hoursaverage, and 75 pglnf for annualaverage and 260 pglm3for 24-hour(EPA, 1982b). Althoughcontrolled exposures to differentconcentrations have shown different effectson respiratoryfunctions, epidemiological studies have provided much of the informationconcerning the effecs of exposureto realisticconcentrations of sulfur dioxideand suspended particulate matter. Variationsin the 24-houraverage of sulfur dioxide (SO) andtotal suspendedparticulate matter (fSP) havebeen associatedwith increasedmortality and morbidity,and reductionsin lung functions. During the first half of this centuryepisodes of markedair stagnationhave resultedin well-documentedexcess mortality in areaswhere fossil-fuel combustion producedvery high levelsof SO2and TSP (EPA, 1982). In one notableepisode 25 Motor vehicleair pollution in Donora,Pennsylvania in October1948, 43% of the populationof approximately 10,000were adverselyaffected. A similar eventoccurred later in Londonwhere concentrationsof SO2and smoke rose above 500 pglm3. The peopleprimarily affectedwere those with preexistingheart and lung disease,and the elderly, althoughwith closerexamination of thesedata, it seemsthat childrenunder 5 yearsold were alsoseverely affected (London Ministry of Health, 1954). Followingthese major episodes,attention was turned to studieson more moderate day-todayvariations in mortalitywithin large citiesin relationto pollutants. Theseacute mortality studies of SO2and particulate matter suggested a dose- responserelationship between 24-hour levels of thesepollutants and excess mortality,particularly at valuesover 500 p1lni. However,new analysisof the LondonWinter data1958-1959 to 197l-1972,controlling for important confoundingvariables such as temperature and humidity indicatesthe absenceof a thresholdlevel for the adverseeffect of British smoke,and a statistically significantpollutant effect on mortalitybelow 150pglm3 was observedio.tro, 1984). Similarresults were reported by other authors(Schwaru and Marcus, 1990;Schwartz, 1991). Evanset al. (1984)summarized data from 23 original cross-sectionalmortality studies and derived a dose-responsefunction to assessthe impacton mortalityof changein particulatelevels. More recentlySchwartz and Dockery (1992),reported an associationbetween TSP anddaily mortalityin Steubenville,Ohio, US. An increasein 100pglm3 in the daily particulatemean was associatedwith a 4Voincrease in mortalitythe next day. The relationship appearedto hold at levelswell below the currentnational air qualitystandard (ISP 24-hourmean = 250 pglm3). Shortterm peakconcentrations of SO2and particulate matter may also increase morbidity, especiallyin individualswith highersensitivity than the general population,such as thosewith asthmaand chronicbronchitis. Basedon epidemiologicalstudies :rmong these populations, a minimumlevel of black smoke and SO2of 250 pglm3 is estimatedto be neededto produceeffects, including exacerbationof symptomsand asthmaattacks, although effects may be observedat lower levelsamong highly-sensitive bronchitis patients WHO, 1987c). Results from studiesof hospitalization@ates, 1983) arid emergency room visits alsotend to supportthis association(Samet, 1981). More recentstudies conducted close to a steelmill in Utah wherePM,s (particulatematter < 10 pm) wasthe only significantpollutant, have pointed out the adverseeffects of PMto on hospital admissionsfor respiratorydisease @ope, 1989), and on mortalityfor respiratory relatedcauses (Archer, 1990). Using datafrom the HealthInterview Survey (HIS), collectedover a 6 yearperiod (1976-1981),Ostro (1989)calculated that an increasein the annualmean of t pglnr3in fine pafiiculates(< 2.5 pm) couldbe associatedwith a3.2% increasein acuterespiratory diseases in adultsaged 18{5 years. 26 Health effects of air pollution In somestudies, observed deviations in lung functionlevels of childrenhave been associatedwith short-termfluctuations in particulateconcentration (WHO, 1987c). From datacollected by Dockeryet d. (1982)during air pollutionepisodas it can be calculatedthat in the mostsensitive children (approximately 25% of his study population),there was a deficit in lung functionat least4 timesgreater than in thoseof averagesensitivity, corresponding to a decreasein FEVI of 0.39 ml per eachincrease of L y,glnf of exposureGSP). The minimumlevel for effectwas judgedto be 180pglm3 TSP. In a studyconducted among asthmatics, inhalable particulatematter (3 = 10 pm) was associatedwith reductionsin PEFRand increasedsymptoms and medication use (Pope,submitted 1990). Studieson long-termhealth effects have related annual means ofSQ and particulatematter to mortalityand morbidity. Ecologicalstudies of the relationshipbetween sulfur dioxide-and-particulatelevels and mortalityftom cardiorespiratorydiseases have usually indicated that this complexof SO2and TSP accountsfor approximately4% of the variationin deathrates between cities (WHO, 1987c). Many factors,such iui differencesin smokinghabits, occupation or socialconditions may contributeto the disparitiesin deathrates attributed to SO, andparticulate, but the resultsof studiescarried out in differentparts of the world imply a relativelyconsistent association between long-term residence in more pollutedcommunities and increasedmortality rates. Recently,a study comparingdifferent areas of Rio de Janeiro,Brazil found a significantdifference in infant mortality from pneumoniaassociated with averageannual level of particulate@enna and Duchiade, l99l). Community-basedstudies conducted among adults and children have indicateda detectableincrease in the frequencyof respiralorysymptorns and illne.ssesin communitieswhere annualmean concentrations of both black smokeand SO, exceed100 pglm3. Severalstudies investigated the relationshipbetween respiratoryillness and symptomrates, and pollutant levels. In a studyconducted amonga preadolescentpopulation aged 6-9 years,living in six US cities (Ware et al., 1986),frequency of chroniccough was significantly associated with the annualaverage concentration ofthese air pollutantsCISP, TSO4, and SO) during the yearpreceding the examination(Figure 4). The maximumlevel observed were 114 pglm3for TSP, 68 pglm3for SO2and 18 p"glrrf for total sulfates (ISO+). Ratesof bronchitisand composite measure of respiratoryillness were significantlyassociated with averageparticulate concentration. Similar results havebeen eonfirmed in a secondcross-sectional survey of Lhesame population @ockeryet d., 1989). A subsetwith asthmaand permanent wheeze experienced a higher rate of pulmonarysymploms in relationto increasedpollutants. There was no evidenceof impairedlung functionassociated with pollutantlevels. Other studiesconducted over a periodof yearshave shown an associationbetween the 27 Motor vehicleair pollution Figure4. Plotof adjustedfrequency of chroniccough againsttotal particulate levels. 175 150 H R 125 R - 7 .T 1L 3 1oo KL o p ltilK .K 3ru TT -E 50 W s s 0 25 50 75 100 125 150 MEANTSP (pg/m3) . The plotincludes 27 region-cohortsagainst mean TSP concentration duringthe previousyear, with between-cities regression equation. (P=Portage,T=Topeka; W=Watertown; C=Carondolet; L=other St Louis; R= SteubenvilleRidge; V- SteubenvilleValley; K=Kingston; H=Harriman) Source'.Ware et al 1986 magnitudeof lung functionchanges and the level of pollution(WHO, 1987c), howeverthere is no firm conclusiongiven the lack of accurateexposure measurement.In many cities of Latin America, particulatelevels greatly exceed the standardguidelines for this pollutant@omieu et al., 1991). In a study conductedin Chile (SERPLAC,1989), comparing Santiago (where particulate levelsare high) and a controlcity, resultssuggest an associationbetween respiratorysymptoms and lower respiratoryfunction parameters, and PMls levels. However the lack of air pollutant measurementsin the control city limits the interpretationof the data. Thereis somegrowing evidencethat chronicexposure to smokemay play an importantrole in the genesisof chroniclung disease.In a studyconducted among adultBritish residents,Lambert et al. (1970)found a higherprevalence rate of chronicbronchitis in residentsof areaswith heavierair pollution, independentlyof cigarettesmoking, although an interactingeffect was also present. Resultsfrom 28 Health effects of air pollution other correlationstudies tended to suggestthat areaswith higherpollution levels are associatedwith higherlevels of chronicbronchitis, although the interpretation of theseresults is limited by the crudeexposure mqsurement. In developing countries,prevalence rates of chronicbronchitis often appearto be muchhigher than in industrializedcountries and to havesex ratiostending to 1, which cannot be explainedsolely by cigarettesmoking @umgartner and Speizer,1991). Althoughexposure to multiplerisk in developingcountries may be muchhigher than in developedcountries these results suggestthat exposureto indoor smoke pollution,which is muchmore commonamong women, may largelyaccount for the differences. Most of the healtheffects described above referred to coal and industrialemission particulates.It is importantto notethat the compositionof particulatesdue to vehicleemission will havea distinctcomposition and therefore potentially a slightly differenthealth impact. However,there is very limited dataon this topic. Effectsof exposureto dieselengine exhaust on the lung havebeen reviewed by Calabreseet al. (1981). Decreasein pulmonaryfunctions (FEV, andFVC) in workersexposed to dieselengine fumes have been observed, however the decrementwas reversibleafter a few dayswithout exposure.There are conflicting resultson the possibleeffect on the lung of chronicoccupational exposure to dieselengine exhaust. Somestudies showed decrements in lung functionsand increasedprevalence of respiratorysymptorns (IARC, 1989). A follow-up study amongworkers in heavyconstruction equipment showed a highly significant overallexcess of deathsfrom emphysema(116 observed,70.2 expected) and this excesswas higher among men with longermembership in the union. However, there was no data on smokinghabis and the author notedthat they were unableto estimatethe degreeto which exposureto dieselemissions (as distinct from other occupationalfactors, such as exposureto dust)might havecontributed to the excessmortality from emphysema(Wong et al., 1985). Otherstudies on exposure to dieselparticulate have emphasized the risk of pulmonarycancer in animals (Adler and Carey, 1989). At the communitylevel, automotiveemissions cannot be consideredin isolationespecially because of their synergisticchemical and physical interactionswith emissionsfrom stationarysources and vegetation,giving rise to secondarychemical products such as acid aerosols(HEI, 1988). In summary,WHO (1987c)has determined the lowest-observed-effectlevel for short-terrnand long-term average air pcllution measurements(fables 4:5); however,recent findings suggest that adversehealth effects may occur at lower concentrations.Several studies provide sufFrcient information to allow a quantitativeevaluation of the healthimpact of particulatematter and have been usedfor risk assessment(Kleinman et al., 1989;Ostro et al., 1990;Romieu et al., 1990). However,these estimates are only approximatebecause several factors 29 Motor vehicleair pollution Table4. Summaryof effectson humanhealth of lowest-observed-effectlevels of sulfur dioxideand particulate matter (short-term exposure). 24-hourmean exposure to: total Soz smoke suspended thoracic Effect particulates particles (pglm3) 0rglm3) @eh'f) Qtgtm3) Excessmoftality 500 500 Increasedacute respiratorymorbidity 250 250 (adults) Decrementsin lung r80 110 function(children) Source:WHO, 1987c Table5. Summaryof effectson humanhealth of lowest-observed-effectlevels of sulfur dioxideand particulate matter (long-term exposure). Annualmean exposure to: total Soz smoke suspended Effect particulates 0.g/rn3) @elt13) @gkrr3) Increasedrespiratory 100 100 symptomsor illness Decrementsin lung i80 function Source:WHO, 1987c 30 Health effects of air pollution may interactin particulatecomposition, and because synergy with otherpollutants may haveoccurred. Also, it is not clearwhether long-term effects can be related simplyto annualmean values or to repeatedexposure to peakvalues. Aci.daerosols Becauseof their small size(fine particles),acid ambientaerosols tend to depositin the distallung airway and airspace.Some neutralization of the dropletscan occur beforedeposition, due to normalexcretion of endogenousammonia into the airways. Depositedfree H+ reactswith componentsof the mucusof the respiratorytract changingits viscosity;the unreactedpart diffrrsesinto the tissues (WHO, 1987c). Beginningin 1986,direct measurementsof sulfuric acid aerosolsand nitric acid vaporhave been made in differentlocations in North America. Thesedata have shownthat in the summer,usually when the 03 is elevatedand the humidity is high, peaksofthese acidsare occurringat groundlevel, lastingfor severalhours @ates,1991). Few measurementshave been made in otherparts of the world, thereforeit is difficult to know the extentof the problem. It is well establishedin animalexperiments and controlledhuman studies that acid aerosolshave a deleteriouseffect on respiratoryhealth. Lippmann(1989c) reviewedrecently the stateof knowledgeof theseeffects. Alterationof lung functions,particularly increase in pulmonaryflow resistanceoccurs after acute exposure.Sulfuric acid (H2SOa)appqus to be more potentthan any of the sulfate saltsin term of increasedairway irritancy (WHO, 1987c). Acid aerosolshave alsobeen shown to modify particleclearance although the mechanismis not yet well established(Folinsbee, 1989). Basedon the epidemiologicaldata collected during the London-smogepisodes, it hasbeen established that excessmortality in Londonwas more closelya.ssociated with British smoke(reflectance data) than with SO2. A reanalysisof the London- Smogmortality data in relationto exposureto acid aerosolssuggests that the SOo- wasthe componentof greaterhealth significance (Ihurston et al., 1989). Also, peaksof acid aerosolsobserved in Canadaduring the summercould have been responsiblefor the associationobserved between sulfate levels and acutehospital admissions,to the extentthat sulfateconstitutes a surrogatemeasurement for su!furicacid aerosols@ate-s and Sitzo, 1987). Changesin lung functionin relationto acid aerosolsexposure have been studied in children. Raizenneet al. (1989)report a 3.5 to 1Vodecrement for FEVt and PEFRassociated with air pollutionepisodes with maximumvalues of 286 p,gllin.-" (0.143ppm) of C,3,47 .7 pglm3HrSOa and 550 nmole/m3of H+. Asthmaticsare 3I Motor vehicle air pollution more sensitivein termsof changesin lung functionsthan healthy people, and vigorousexercise potentiates health effects at a given concentration.The lowest demonstratedeffect level for sulfuric acid was 100pglm3 with mouthpiece inhalationand intermittent exercise (Hackney, 1989). A preliminaryanalysis of datafrom Koeniget al. (1989)collected among allergic children, showed that exposureto HrSo4 aloneor in associationwith So2 causedsignificant changes in lung functionswhereas exposure to relativelyclean air or Se in the absenceof acid aerosoldid not. Recentstudies by ostro et al. (1991)in Denverhave producedevidence that aerosolH+ levelswere associatedwith worseningasthma. Acid aerosolsseem to act synergisticallywith 03. stern et al. (19s9)investigated respiratoryhealth effects associated with ambientsulfates and 03 in two rural canadiancommunities in 1983-1984.Respiratory health was asiessed by the measurementof lung functionsand by evaluationof the child's respiratory symptomsand illnessusing a parent-completedquestionnaire. There was a significantdifference in the level of Se, SOo-and NO, betweenthe two communities.children living in the communitywith the highestlevels of contaminants,had a significantdecrement in lung functionspiuameters e% fot FVC, and L.lVofor FEVr). In summary,it seemsthat the role of secondaryproducts such as acid sulfateare stronglyinvolved in the adverseeffects or oe SQlparticulatecomplex (Spengler et al., 1990). Betterspecification of theseeffects are needed,especially on the genesisand evolutionof chronicpulmonary diseases. substancespreent in exhaustgas that producetoxic systemiceffects. CarbonMonoxide carbon monoxideis rapidly absorbedin the lungsand is takenup in the blood, whereit is boundto haemoglobin(rIB) with the formationof carboxyhemoglobin (coHB) thus impairingthe oxygencarrying capacity of blood; the dissociationof oxyhemoglobinis alsoaltered due to the presenceof coHB in the blood thereby further impairingthe oxygensupply to the tissues(the affinity of haemoglobinfor Co is about240 timesthat of oxygen). The main factorsconditioning the uptake of co are its concentrationin the inhaledair, the endogenousproduction of co, the intensity of physicaleffort, body size,the conditionof the lungs,and the barometricpressure. Table 6 presentsthe expectedcoHB levelsafter exposureto co concentrationsfrom 11.5to 115mg/m3 during differenttypes of phyJical activity. In absenceof co exposure,coHB concentrationsare approximately 0.5%, andone-pack per day cigarettesmokers may achievecoHB saturationof 4 to 7 percent(wHo, 1979). To preventcarboxyhemoglobin levels exceeding 2.5%-3voin non smokingpopulations, the following guidelinesare proposed: a 32 Health effects of air pollution Table6. Predictedcarboxyhemoglobin levels for subjectsengaged in differenttypes of work. Carbonmonoxide PredictedCOHb level concentration for thoseengaged in: Exposure time sedentary light heavy ppm mg/m3 work work work 100 115 15 minutes t.2 2.0 2.8 50 57 30 minutes 1.1 1.9 2.6 25 29 t hour 1.1 1.7 2.2 10 11.5 8 hours 1.5 1.7 1.7 Source:WHO, 1987d maximumpermitted exposure of 100mg/m3 for ( 15 minutes;60 mg/m3 (50 ppm) for < 30 minutes;30 mg/m3(25 ppm) for 3 t hour; 10 mg/m3 (9 ppm) for 8 hours(WHO, 1987d). The main effectof CO is to decreasethe oxygentransport to the tissues. The organsdependent on a largeoxygen supply are mostat risk, and in particularthe heart and the central nervoussystem, as well as the foetus. Four types of health effects are reportedto be associatedwith CO exposure: neurobehavioraleffects, cardiovascular effects, fibrinolysis effects, and perinatal effects. Carbonmonoxide leads to a decreasedoxygen uptake capacity with a decreasedwork capacityunder maximal exercise conditions. Accordingto availabledata, the COHB level requiredto inducethese effects is approximately 5% (WHO, 1979). Someauthors (Beard and Wertheim,1967) have reported an impairmentin the ability to judge correctlyslight differences in successiveshort time intervalsat lower COHB levelsof 3.2 to 4.2%. At this level, subjectsmay misssignals they wouid not havemissed when starting a task. Subjecawith previouscardiovascular disease (chronic angina patients) seem to be the most sensitivegroup to CO exposure.In a recentstudy, Allred et al. (1989) investigatedthe effectsof CO exposureon myocardialischemia during exercisein 63 men with documentedcoronary artery disease. Results showed a decreasing 33 Motor vehicle air pollution dose-responserelationship between the lengthof time to the onsetof anginaand coHB level. The lengthof time to the onsetof anginawas reduced by 4.2% for coHB levelsof 2vo andby7 .lvo at 3.9vocoHB level. This studyshows that COHB levelsas low as 2% canexacerbate myocardial ischemia during exercisein subjectswith coronaryartery disease. Similar effectshave been demonstrated in patientswith intermittentclaudication from peripheralvascular disease (Aronow, 1974). A retrospectivecohort study conducted among bridge and tunnel offrcers (n=5,529) exposedto CO showeda 35% excessrisk of arterioscleroticheart diseasemortality amongtunnel officers when compared to the New york City population. Two factorscontributed to this excessrisk: the exposure(current) to CO of tunnelsoffrcers and the movementinto a critical higherage group. There was a reductionof mortalityafter decreaseof exposure(more ventilation in the tunnel)(Stern, 1988). Table7 summarizesstudies relating human health effects to differentlow{evel exposuresto carbonmonoxide. The classicsymptonN of co poisoningare headache and dizziness at coHB levels between10 and 30vo andsevere headache, cardiovascular symptoms, and malaise over about30%. Above about40% there is considerablerisk of comaand death. co exposuremay alsoaffect the foetusdirectly throughoxygen deficit without elevationof coHB level in the fetal blood. Dlring to high co levels the mother'sHB lessreadily gives up its oxygen,with "iposuiJ consequent lowering of the oxygenpressure in the placenta,and hence also the foetalblood. Researchhas mainly focusedon the effectof cigarettesmoking during pregnancy.The main effectsare reducedbirth weight(Mathai et al., 1990;Ash et al., 19g9;Hebel et al., 1988)and retarded postnatal development (Campbell et al., l98g). In summary,average carboxyhemoglobin levels in the generalpopulation are aroundL.2-l.5Vo (in cigareuesmokers around 34%). Below 10%COHB, it is mainly cardiovascularand neurobehavioraleffects that havebeen evaluated. The aggravationof symptomsin anginapectoris patients, which is a major public healthconcern, may occur at levelsas low as 2% coHB. Decreasedwork capacityand neurobehavioral function have mostly been observed uound 5%. Low birthweighthas been related to cigarettesmoking during pregnancywith the hypothesisthat increasedmother's coHB couldhave a role in this adverseeffect, howeverthere is no estimationof the impactof specificcoHB level on the decreasein birth weight. Basedon ambientco concentration,time of exposure, andphysical activity type, the expectedlevel of coHB canbe derlr'ed(fable 6), andused to determinethe healthimpact on the populationof specific CO exposure. 34 Health effects of air pollution Table 1. Humanhealth effects associated with lowleve! carbonmonoxide exposure: lowest-observed-effectlevels Carboxyhemoglobin concenEation(%) Effects 2.3- 4.3 Statisticallysignificant decrease Q-7%) ia tle relation betweenwork time and exhaustionin exercisingyoung healthymen 2.9- 4.5 Statisticallysignificant decrease in exercisecapacity (i.e. shortenedduration of exercisebefore onset of pain) in patients with angina pectoris and increasein duration of angina attacks 5-5.5 Statisticallysignificant decrease in maximaloxygen consumptionand exercisetime in young healthy men during strenuousexercise <5 No statisticallysignificant vigilance decrements after exposureto carbonmonoxide 5 -7.6 Statisticallysignificant impairment of vigilancetasks in healthyexperimental subjects 5-17 Statisticallysignificant diminution of visualperception, manualdexterity, ability to learn, or performancein complexsensorimotor task (e.g. driving) 7 -20 Statisticallysignificant decrease in maximaloxygen consumptionduring strenuousexercise in young healthymen Source:WHO, 1987d lzad The contributionof alkyl lead additivesin motor fuels accountsfor the maior part of all inorganiclead emissions. An estimated80-90Vo of lead in ambientair derivesfrom the combustionof leadedpetrol. The degreeof pollutionfrom this sourcediffers from countryto country,depending on motor vehicledensity and efficiencyof effortsto reducethe leadcontent of petrol (WHO, 1987e). About l% of the lead in petrol is emittedunchanged as tetraalkyllead(organic lead). Thereis in addition,some evaporation of organiclead from the engineand fuel tank. Concentrationof tetraalkylleadamounting to morethan 10%of the total lead contentof ambientair hasbeen measured in the immediatevicinity of service stations(NSIEM, 1983). The WHO guidelinevalue for long-termexposure (e.g annualaverage) to leadin the air is 0.5-1.0pglm3 (WttO, 1987e). 35 Motor vehicle air pollution Most of the lead in ambientair is on fine particles(< 10 pm). For adultsthe retentionrates of airborneparticulates range from 20Voand 60%. Young children inhaleproportionately higher daily air volumeper unit measure(weight, body area)than do adults @arltrop, 19'12). It was estimatedthat children have a lung depositionrate of leadthat canbe up to 2.7 fold higherthan adultson a unit body massbasis. The proportionof lead absorbedfrom the gastrointestinaltract is about10% to 15% @abinowitzet al., 1980)in adults,whereas levels of 44-50% havebeen reported in children(Ziegler et d., 1978). It is influencedby dietary intake. Fasting,diets wittr low levelsof calcium,vitamin D, iron, andzinc (Mahaffey,1990) have been shown to increaselead absorption.The nonexcreted fractionof absorbedlead is distributedamong three compartments: blood, soft tissues,and mineralizingtissues (bones, teeth). About91% of the leadbody- burdenin adultsis locatedin the bones,compared with about70Vo n children. Nonabsorbedlead is excretedin the faeces. Of the absorbedfraction 50 to 60% is removedby renaland biliary excretion. The concentrationoflead in deciduous teethprovides a usefullong-term record of leadexposure in children. Organic leadcompounds, (tetraalkyllead and its metabolites),are volatile andliposoluble and are mainly takenup via the respiratorytract. The absorptionby the lung is rapid andpractically complete. Absorptionthrough the skin is alsoimportant. Tetraalkylleadis metabolizedin the liver andother tissuesto trialkyllead,which is the mosttoxic metabolite(NSIEM, 1983). Animal and epidemiologicalstudies have demonstrated that leadexposure may act on differentsystems, principally heme biosynthesis, the nervoussystem, and other systemssuch as the cardiovascularsystem (blood pressure). Infants and young childrenless than five yearsold are particularlysensitive to lead exposurebecause of its potentialeffect on neurologicaldevelopment. The effectof leadon hemebiosynthesis and erythropoiesis is mainly at the level of threeenzymes: it stimulatesthe mitochondrialenzyme delta-aminolaevulinic synthetase(ALAS); it inhibitsthe activity of the cytoplasmicenzyme delta- aminolaewlinicacid dehydrase(ALAD) which resultsin an accumulationof its substrateALA (this interferencewith hemesynthesis may occur at levels ( 100 y"gll); it interfereswith the functioningof intramitochondrialferrochelatase, responsiblefor the insertionof iron into the protoporphyrinring, therefore resultingin an increaseof erythrocyteprotoporphyrin or zinc protoporphyrinin blood (Figure5). Anemiais a frequentoutcome of chroniclead intoxication. Apart from this hematologiceffect, lead also exertsan adverseeffect on the endocrinesystem including the gonadaland reproductive systems @ohn et al., 1982),it depressesthyroid function(Iuppurainen et al., 1988),and impairs hepaticmetabolism of cortisol(Saenger et al., 1984). In youngchildren, lead 36 Health effects of air pollution Figure5. Effectsof leadon hemebiosynthesis. MITOCHONDRION HEME APb {1 ",J,5?lStv AMINOLEVULINICACID (ALA) ALA COPBOPORPHYRIN I pb DEHYDRASEF- (INCREASE) (DEoREASE) | Y PORPHOBILINOGEN. Source:EPA. 1986 ffiosxts exposureis alsoassociated wittr a decreasein the biosynthesisof l,25{ihydroxyvitamin D, an importantmetabolite of vitamin D (Mahaffeyet al., 1982). The centralneryous system is the primary targetorgan for leadtoxicity in children. Exposureto high concentrationsof lead can result in an encephalopathy which is more frequentin childhoodlead poisoning than in adultpoisoning. The r&Nonmay be dueto the easewith which leadcrosses the blood-brainbarrier in children. Encephalopathyhas occurred in childrenat blood leadlevels in excess of 800 to 1000pgll (NAS, 1972). The brain seemsmore sensitiveto alkyl lead exposure(NSIEM, 1983). Exposureof childrento lower concentrationsof leadmay produceneuro- physiologicaldisorders, including impairment of learningability, behavior, intelligenceand fine motor coordination.This work hasbeen recently reviewed (Grantand Davis, 1990;Davis and Svendsgaard,1987; ATSDR, 1988). Needlemanand colleagues(1979), in a communitybased study of childrenin Bostonin whom previousexposure to leadwas estimatedfrom examinationsof deciduousteeth, reported evidence of lead-relatedneuropsychological deficits. This negativeassociation between tooth-lead level andmental development was reportedin subsequentstudies (Winneke et al., 1983,1984). However,in other studies(Smith et al., 1983;Harvey et al., 1984),correcting for socialenvironment 37 Motor vehicleair pollution greatlyattenuated this inverseassociation. More recently,some authors (Hawk et al., 1986;Fulton et al., 1987)reported a significantinverse linear association betweencognitive ability andblood lead,with no evidentthreshold level of exposure.The meanblood leadlevel of the highestlead group in the studyof Fulton et al. (1987)was 221pglI, suggestingthat IQ deficia are relatedto lead exposureof <250 1tgll. In agreementwith thesefindings, a recentstudy conductedin Mexico city amongschool children, from low to mediumsocial statusand aged9 to 12 years,showed a strongnegative correlation between blood leadlevel and intellectualcoefficients and teacher grading without evidenceof thresholdlevel (Munozet al., submitted).Although none of the abovestudies can providedefinite evidence that low-levellead exposureis linked to reduced cognitiveperformance in children,the overallpattern of findingssupports the conclusionthat low-levellead exposure is relatedto neurobehavioraldysfunction in children. In addition,a follow-up investigationof the childrenpreviously studiedby Needleman,showed that, l1 yearslater, high-leadchildren were significantlymore likely to drop out of high schooland have a readingdisability (Needlemanet d., 1990). This studyhas been criticized because of potentialbias (Good, 1991),however the resultssuggest that early lead exposuremay result in long-termneurobehavioral impairment. Basedon this body of datathe lowest-observed-adverse-effect-levelhasbeen definedas possibly< 100pgll (ATSDR, 1990). Lead is transportedto the foetusacross the placentasince there is no metabolic barrier to fetal lead uptake. Furthermorethe amountof lead maternally circulatingfor fetal uptakemay actuallybe higherthan usual since part ofthe lead storedin boneis reabsorbedinto blood duringthe pregnancy.Prenatal exposure to lead,produces toxic effectson the humanfetus including reductions in gestationalage, birthweight, and mental development. These effects occur at relativelylow blood leadlevels. An inverseassociation between maternal (or cord) blood leadlevels and gestational age was reportedby differentauthors (McMichaelet al., 1986;Dietrich et al., 1986,19S7b). Basedon risk esrimates of McMichaelet al. (1986),the risk of prematuredelivery increases by approximatelyfour fold as cord or maternalblood leadlevel increasesfrom 3 80 to > 140p"gll. Datafrom the Cincinnatistudy suggest an inverserelationship of prenatalmaternal blood leadlevel andbirthweight and postnatal growth rates @ietrich et al., 1987a;Shulka et al., 1987). Otherstudies also support this inverseassociation @ellinger et al., 1984;Ward et al., 1987). A numberof longitudinalstudies currently underway have investigated the effect of early lead exposureand developmentaleffects. Bellingeret al. (1987, 1989),in Boston,studied the relationshipbetween umbilical cord blood lead andearly cognitivedevelopment between 6 and24 monthsof age. Lead concentrations 38 Health effects of air pollution were measuredin249 umbilicalcord blood s:rmplesof infantsborn to middle and upper-middleclass parents. Cord blood leadlevels were categorr,edas low (mean=180 pgll), mid (mean=650p.elD and high (mean=1460 y.gll). After accountingfor factorsrelated to infant developmentsuch as, mother'sage, race, IQ, education,care giving environment,social class, and infant's sex, birthweight, birth order andgestational age, there was a significantinverse relation of performanceon the BayletMental development Index (MDI) at 6, L2 urd 24 monthsand cord blood level (Figure6). Figure6. Meanmental development index scores at fourages in infantsaccording to the leadlevel in umbilical-cordblood. Cord-bloodlead group Groupe de plomb6miecordale 120 a--O Low-Faible mean = 146 uo/l A - l! lvledium-Moyenne mean = 180 utl O--.o' High-Elev6e mean = 650 ug/1 .) 0) 3 rre X o ; o I dt tz o q, o v o 6 5 108 f 104 s 6121824 Age at testing (months) - " Scoresare least-squaresmeans obtainable by regressing MentalDevelopment index scores on the cord-bloodlead group and l2 variablesconsidered to be potentialconfounders. Error barsrepresent 1 SD. For clarity,bars extend only in one direction. Source:Bellinger et al, 1987 39 Motor vehicle air pollution The MDI is a compositescale to assesssensory-perceptual acuities, memory, learningability, verbalcommunication and other cognitivefunctions (Shy, 1990). The deficit in MDI betweenthe low- andhigh-exposure groups was between 4 and 7 points. Postnatalblood-lead levels showed no associationwith MDI deficit. Children in the lower socioeconomicstratum were adverselyaffected at lower levelsof prenatalexposure (Needleman, 1989). Thesefindings are supportedby other studies@ietrich et al., 1987a,Erhnart et al., 1987). Anothermajor prospectivestudy is beingconducted in Port-Pirie,South Australia among a cohort of 537 childrenborn during 1979 to 1982to womenliving neara leadsmelter (McMichaelet al., 1988). Bloodsamples were collected from the mother, antenatallyand at delivery,from the umbilicalcord and at age6, 15,24 months and every yearsthereafter. At the ageof two, the meanblood lead concentration was 212 y"gll with a rangeof 49 pgll to 566 p.g/|. The developmentalstatus of eachchild wastested using the McCarthyScale of Children'sAbilities (MSCA). Maternalintelligence, care giving environmentwere alsoevaluated. The blood lead concentrationat eachage, particularly at two andthree years and integrated postnatalaverage concentration were inversely related to developmentat the ageof four. Independentlyfrom otherfactors that may affect child development,subjects with an averagepostnatal blood lead concentration of 308.7 pgllhad a cognitive score7.2 pcrintslower than those with an averageconcentration of 102.9p,gll (Figure7). Figure7. Linearrelation between the integratedpostnatal average bicod leadconcentration and the generalcognitive index lineof bestfit r'o . = l-- Cnanoe | Meanscore = 107.1 7.2 u"nits | ,ou I 100 51.7 103.3 206.6 309.9 516.5 I Changein PbB I Antilogblood lead concentration (pgn) "Generalcognitive index Source:Mcvichael et al, 19BB 40 Health effects of air pollution Similar deficit occurredin the perceptualperformance and memory score. There was no evidencethat cognitivefunction at age4 was more influencedby recent than earlierpostnatal blood leadlevels. Within the rangeof exposurestudied, therewas no evidenceof a thresholddose for an effectof lead. Theseresults suggestthat insreasedexposure to leadresults in developmentaldeficit, not just developmentaldelay. Althoughthe cognitiveand neurosensory effects of low- level blood lead are particularlydifficult to studymainly becauseof the variety of testsused, and the numberof differentfactors that may affect child development, thereis an impressiveconvergence of animaland human studies (Shy, 1990). Grant andDavis (1987)concluded that neurobehavioraldeficits and reductionin gestationalage and birth weightare associated with prenatalinternal exposure levels,indexed by maternalor cordblood lead concentration of 100to 150pgll andpossibly lower. In additionto the aboveassessments of the relationshipof leadto cognitive functionsand behavior,other aspectsof lead-associatedneurotoxicity have been examined. Hetring thresholdsin childrenappear to be adverselyaffected by lead. In the analysisof NHANESII databy Schwartzand Otto (1987),the probability of elevatedhearing thresholds increased with increasingblood levelsacross the entirerange of levelsstudied ( < 40 to > 500pgll). Exposureto high concentrationof leadmay leadto functionaldisorders of the gastrointestinaltract; a commonsign of acutepoisoning is colic. Leadmay also producedamage in the kidneys,which lead to increasedurinary excretion of aminoacids, glucose and phosphate lFanconi syndrome). After long exposurethe injury may enterinto a chronicstage with fibrosisand arterioscleroticchanges in the kidney(Choie and Richter, 1980). Epidemiologicaland animal data indicate that lead increases blood pressure. In a studyconducted in the US, systolicand diastolic blood pressure were significantly relatedto blood lead in white malesaged20-74 years, after adjustingfor potential confounders(Pirkle et al., 1985). Thesefindings have been confirmed by another study(Pocock et al., 1988);however the causalrelationship between blood lead levelsand blood pressureis still unclear. The lowest-observed-effectslevels for lead-inducedhealth effects in adultsand children are shownin Tables8-9. In summary,the adverseeffect of leadexposure in the early neurobehavioral developmentis of primary concern. It occursat levelswell below those considered"safe" in recentyears. Therecan be little doubtthat exposureto lead, evenat bloodlevels as low as 100-150y,gll, andpossibly lower, is linkedto undesirabledevelopmental outcomes in humanfetuses and children @avis and Svendsgaard,1987).The mostclearly identified effect has been lower scoreson 4l Motor vehicle air pollution Table E. Summaryof lowest-observed-effectlevels for key lead-inducedhealth effects in adults. Lnwestobsrved- Heme syntbesie Reproductivo effect level @bB)' aad hematological Effets on the functiol Cerdiovarcular @etdt) effectB Neurological effwtr kidney cffects efrets 100-120 Eocephalopathic Chronic sigm and symptoms oephropathy 80 Frank anemia 60 Femalo reproduc$ve effect6 50 Reduced Overt Altered hemoglobin mbencephalopatbic testicular projoctiotr neurological function symptomg 40 Increased urinry Peripheral nerve ALA md elevated dysfunction (slowed coproporphyrins nerve conduction) 30 Elevated bl@d presre (white males, aged t10-59) 25-30 Erythrtryte protoporphyritr (EP) elevation in males t5-20 Erytbrcyte protoporphyria @P) elevation in females <10 ALA-D itrhibitiotr , rPbB = Blmd lead concentrations. I pg/dl - I0 pgll Source: ATSDR,1990 42 Health effects of air pollution Table 9. Summary of lowest-observed-effectlevels for key lead-inducedhealth effecs in children. Lowest-obs€rved- effect level (PbB)r Hemc syntbesisaad Neurological and Gastroirtestinal tpgldl) hematologicaleffects related effects ReDAlsyslem effects effects 80-100 Encephalopathicsignr Chronic nephropathy C.olic and and symptoms (rnimaciduris, etc.) oth€r overt gestrointestiral symptoms 70 Frank anemia 60 Peripheral neuropatb.ies 50 ? & Redrced heooglobil Peripberal nervo synthesis dysfunction (slowed NCVs) E!evated CNS cognitive effects coproporphyrin (IQ deficits, etc.) Increased urimry ALA 30 Vit.nin D metabolism inl,erfemco l5 Erythnryto Altered CNS protoporphyrin electrophysiological elevation resPonsea 10 ALA-D inhibition MDI deficits, reduced ? gestationalage atrd birth weight (prenatal exposure) Py-S-iS activity , inhibitioo ? 'PbB = Blood lead concentrations. opy-S-N = Pyrimidine-5'-nucleotidase. lp.gldl = l0 pgll Source:ATSDR, 1990 43 Motor vehicle air pollution the Mental DevelopmentIndex (MDI) of the BayletScale of Infant development, poor schoolattainment and lower intellectualcoefficients, reduced gestational age, and lower birthweight. In differentstudies, a dose-responsecurve betweenblood lead level and neurobehavioralimpact has been derived @ellinger et al., 1987, I\{cMichaelet al., 1984, 1988),and can be usedto estimatethe healthimpact of lead exposureat the populationlevel. In termsof implicationsfor public health, an overall 4-point downwardshift in a normaldistribution of Baylet MDI scores would result in 50% more childrenscoring below 80 in this exam. The useof leadin gasolinehas been declining in variouscountries. This was responsiblefor a substantialdecrease of blood leadlevels in the generalpopulation (Annestet ai., 1983). Many countries,especially in the developingworld, are still using leadedfuel. Consideringthat in thesecountries, poor nutritionalstatus and "homeenvironment" may potentiatethe effectof lead exposurein a great proportionof children,there is an urgentneed for regulationand continued researchto identify otherpotential sources of lead exposureand interactingfactors of adverseeffects. and to evaluateinterventions. Substanceswith potential carcinogeniceffect The following substancesare components of automotiveemissions. They may haveother healtheffects, but the sourceof mostconcern is their potential carcinogeniceffect. Benzene Benzeneis a constituentof crudeoii andin Europeis presentin petrol in a proportionof around5 %, occasionallyup to l6Vo, while in the US the benzeneof gasolinedoes not exceed1.5 to 2%. The majorsource of benzeneis emissions from motor vehiclesand evaporationlosses during handling,distribution and storage(WHO, 1987f). Benzeneconcentration in ambientair of residentialareas generallyranges from 3-30pglm3 10.0014.01 ppm) depending on thetraffic. The benzeneintake from the air may thereforerange from 30 to 300 pg. The daily intakefrom food andwater has been estimated to be 100-250pg. People smoking20 cigarettesper day would havea daily increasedintake of approximately600 pg (WHO, 19870. About 50% of inhaledbenzene in the air is absorbed.Due to its high liposolubility,benzene is distributedmainly to fat rich tissuesuch as adiposetissue andbone marrow. Benzeneis oxidizedby the P-45O-dependentoxidase system. Part ofthe absorbedbenzene is exhaledunchanged in breathand part is eliminated in the urine after transformation. 44 Healtheffects of air pollution The toxic effectsof benzenein humansfollowing inhalationexposure include centralneryous system (CNS), hematologicaland immunological effects. Toxic effectshave beenobserved for exposureto very high levels(more than 3200 mg/m3or 1000ppm) with the appearanceof neurotoxicsyndrome. Acute poisoningcan lead to deathwith higherexposure associated with inflammationof the respiratorytract andhaemorrhage of the lung. Persistentexposure to toxic levelsmay causeinjury to the bonemarrow, resulting in pancytopenia.This has beenobserved in severaloccupational studies in which workerswere exposedto high benzenelevels. Benzeneis a knownhuman carcinogen classified as Group 15 ldefinite carcinogen)by the InternationalAgency for CancerResearch (IARC, 1982). Carcinogeniceffect has been reported in workersexposed to benzenewho are more likely to developacute leukemia than the generalpopulation. Assessmentof the risks of exposureto benzenehas recently been reviewed using mathematical methodsof extrapolationfrom high to low exposure(Van Raatleet al., 1982). Using epidemiologicaldata, the differentmathematical models give estimatesof excessleukemia deaths resulting ftom 30 yearsoccupational exposure to I ppm benzeneranging from 3 to 46 per thousand(IPCS, 1990). Estimatedrisks at lower exposure@ailer et al., 1989)range from 0.08to 10 excessleukemia deaths per millionsresulting from lifetimeexposure of I pglm3(approximately 0.0003ppm) of benzene. The Carcinogen,Assessment Group (CAG, US EPA, 1985)estimated, using differentmathematical models, that the "best-judgement"unit risk was8.1'10-6. Thesedata cau be usedto assesshuman risk at low concentrationseen in non- industrialcommunities. Thus, for examplein the Los AngelesBasin where the populationweighted concentration to benzeneis 0.0147mg/mr (0.0046ppm), the addedlifetime risk is estimatedto be 101to 780 casesper million peopleexposed (SCAR,1984). However,this methodof estimatingrisk is not universally acceptedbecause the mutagenicmetabolite of benzenehas not beenidentified and becauseDNA repairsystem may be moreefficient at lower exposureconcentration @ead, 1990). In a recentstudy, Yin et al. (1989)report a significantlyincreased lung cancer,as well as increasedacute myelogenous leukemia. This suggeststhat benzenemight be a multisitecarcinogen in humans,as hasbeen indicated in 5 G-up l: The agent is carcinogenic to humans. This category is used only when there is sufficient evidence of carcinogenicity in humans. That ig a positive relationship has been obsenred between exposure to the agent and cancer in which chance, bias and confounding could be ruled out with reasonableconfidence. 45 Motor vehicle air pollution animalstudies. There is no safelevel for airbornebenzene as benzeneis carcinogenicfor humans(WHO, 1987D. Polycyclic aromatic hydrocarbons(PAHs) Polycyclicaromatic hydrocarbons are a groupof chemicalsformed during the incompletecombustion of wood andfuel. Exhaustfrom dieselengines contains lower concentrationsof somegaseous pollutants but higherconcentrations of particulatebearing organic extracts including polycyclic aromatic hydrocarbons. Other main sourcesof PAHs are cokeproduction and heating with coal and cigarettesmoke Qrigh proportion). Thereare severaihundred PAH; the best- known is benzo[a]pyrene@AP). Polycyclicaromatics are absorbedin the lung and gut. They are metabolizedvia the mixed-functionoxidase system; the latter metabolites:re thoughtto be the ultimatecarcinogens (WHO, 19879). Evidencefrom experimentalstudies shows that manyof thesePAHs are mutagenic and carcinogenic.Epidemiological studies in coke-ovenworkers and coal-gas workershave suggested an increasedrisk of lung cancerin relationto PAH exposure(Steenland, 1986). More recentlya case-controlstudy of deathsamong United Statesrailway workersshowed that workersaged under 65 who had been exposedfor at least20 years,had a smallbut significantlyincreased risk of lung cancer(Garshick et al., 1987). Studiesof populationsexposed to dieselhave been inconclusivebecause of difficultieswith controllingfor smokingand occupational exposures(Read, 1990). However,two recentstudies among workers exposed to automotiveemissions indicated that malesusually employed as truck drivers or delivery men had a statisticallysignificant 50% increasein the risk of bladder cancer(Silverman et al., 1983,1986). Basedon studieson benzo[a]pyreneas index compound,it is estimatethat the upper-boundlifetime cancerrisk will be 62 per 100,000exposed people per pg benzenesoluble coke-oven emission per m3 ambientair. Assuming a0.71% contentof benzo[a]pyrenein these emissions, it canbe estimatedthat 9 out of 100,000people exposed to I mg benzo[a]pyreneper m3 over a lifetime would be at risk of developingcancer. Thereis no safelevel of PAH due to its carcinogenicity,and no knowncancer threshold for Benzo[a]pyrene(WHO, 19879). Benzo[a]pyrenehas been classified as Group 2A,6(probably carcinogenic) by the IARC (1933). 6 Gro,rp 2A. The agent is probably carcinogenic to humans. There is limited evidence ofcarcinogenicity in humans and sufficient evideuce ofcarcinogenicity in experimental animals. 46 Health effects of air pollution Aldehydes Aldehydesare absorbedin the respiratoryand gastrointestinaltract and metabolize Acute irritant effectsof aldehydeson humanvolunteers have been documented. For formaldehycle,these effects include: ocular and olfactory irritation (observed at 0.06 mg/rn3),irritation of mucousmembranes and alterationin respiration (observedat0.l2 mg/m3),coughing, nausea and dyspnea (WHO, 1989). Allergic responseshave been observed as asthmaand dermic allergy. Formaldehyde exposurehas beenassociated with cancerrisk mostly in occupationalsettings. The sitesmost frequentlyencountered are nasaland nasopharyngeal(Vaughan et al., 1986a1986b; Olsen and Asnaes 1986), leukemia (Stroup et al., 1984, 1986;Walrath and Fraumeni1983 1984) brain (Ilarrington and Oakes1984, Stroupet al., 1984;Walrath and Fraumeni, 1984). Excessesof cancercases from other siteshave alsobeen described among occupationally exposed individuals. Formaldehydehas been classified as probably carcinogenic to humans,(Group ze6; uy IARC (1987). Humanexposure to formaldehydeshould be minimized, not only for its probablecarcinogenic effect, but alsofor its potentialfor tissue damage. Epidemiologicalstudies on carcinogenicitythat containsome exposure ^ assessmentimply thatthresholdfor tissuedamage ii about1.0 mg/m3(0.5 mg/m3- 3 mg/m3)(WHO, 1989). Howeverno risk estimateof carcinogenicitycan be madebecause of lackof adequatedata. In summary,animal and epidemiologicaldata conducted in occupationalsettings havebeen used to constructlinear modelsto assesshuman risk of cancerat low concentrationsseen in non-industrialcommunities. These models are availablefor benzeneand BAP exposurebut not for aldehydes.The InternationalAgency for CancerResearch has evaluated the carcinogenicrisk to humansfrom dieseland gasolineemissions, including all componentsin differentexperiments (IARC' 1989). The Agencyconcludes that dieselexhaust may be associatedwith lung and bladdercancer and it hasbeen classified as "probably"carcinogenig 1s humans( Group 2A). Regardinggasoline exhaust, there is no evidenceof an association with a particulzrtype of cancerand it hasbeen classified as "possibly" carcinogenicto humans(Group 287). 7 Group 28: The agentis possiblycarcinogenic to humans.There is limited evidence of carcinogenicity in humansand absenceof sufficient evidencein experimentalanimals. 4'1 Motor vehicle air poilution 4. Conclusions Epidemiologicalstudies have been widely usedto shedlight on the effectsof air pollutantsdue to vehiculartraffic on health. In order to evaluaterisk due to automotiveemissions at the genera!population level, severalfactors have to be considered:exposure, dose, biological effects, dose-response relationship, and proportionof populationexposed. The resultsof somestudies are difficult to interpretbercause of a variety of limitations,mostly regarding exposure assessment andhandling of co-factors. orher studiesprovide enough information to derive dose-responsefirnctions tlat canbe appliedto ambientlevels of specificpollutants in orderto estimateselected health effects. Thesestudies have been referred to in the text. For pollutantsproduced by vehicularemission, such estimates can be madeto assessthe potentialadverse health effects of O., particulate,CO, lead, as well as for the carcinogenicrisk of exposureto benzeneand BAp or pAH. Variouslimitations of theseestimates should be mentioned: l) dose-responsefunctions are populationspecific, and therefore their use in otherpopulations may not be justified, especiallyif derivedfrom only one study. 2) theseestimates do not considerthe potentialinteractive effect of different pollutants. 3) they are only mathematicalmodels and aredependent on differentsets of assumptions. 4) extrapolationof the shapeof the curveoutside of the rangeof observed valuesmay leadto erroneousresults (for instanceit will be difficult to extrapolate to low level eff'ectsif there is no knowledgeof the pre.senceof a thresholdvalue). 5) in somecases, it is difficuitto determinewhich is the mostrelevant exposure measurementfor the healtheffect being studied. 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Absorptionand retentionof leadby infants. Pediaric Research,12: 29-34(1978). 62 Chapter2 Part II E,FTECTSON IIUMANS OF ET{YIRONMEI'{TAL NOISE PARTICIJLARLY FROM ROAD TRAFTIC RagnarRylander" Introduction Soundsprovide an essentialcontact between humans and the surroundingworld' Awarenessof familiar sounds- the wavesat sea, footstepsof family membersand musicinduces reactions of recognition,pleasure and satisfaction.The harmony betweennormal soundsand periods of quietnessis also important, particulady for music. Other sounds- creakingfloors in an empty house,sudden bangs and unpleasantmusic - induce alertness,fear and annoyance. Suchsounds are generallyreferred to as noise. As this is a subjectiveassessment, it is clearthat definitions of, as well as adversereactions to different soundsvary between individuals due to experience,attitudes and knowledge. Soundhas particular characteristicswhich distinguishit from other kinds of environmentalpollutants, such as chemicalagents. Sound- or noise - is part of everyday life and is necessuyfor the normalfunctioning of ttrehuman body. RagnarRylander, Profqssor in EnvironmentalMedicine, University of Gothenburg,Sweden 63 Motor vehicle air pollution Personswho are kept under conditionsof completesilence may developsymptoms of mentaldisorder - absenceof auditory communicationdue to deaftressmay indygepersonality changes and conditionsof completesilence can be experienced as frightening. As the soundlevels increase in intensity,negative effects start to dominateand the ultimateeffect is a direct physicaltrauma when the receptor organis destroyed.Although the positivereactions after soundexposure are important, it is usually the negativeeffects that attract attention. Noisehas alwaysbeen an importantenvironmental problem for man. In ancient Rome,rules were in existenceas to the noiseemitted from the ironedwheels of wagonswhich batteredthe stoneson the pavement,causing disruption of sleepand annoyanceto the Romans. In MedievalEurope, horse carriages and horse back riding were not allowedduring night time in certaincitiqs to ensur"a peaceful night's sleepfor the inhabitants. However,the noiseproblems of the pastare incomparablewith thoseof modern society. An immensenumber of carsregularly cross our citiesand the countryside.There are heavily laden lorries with dieselengines, badly silenced both for engineand exhaustnoise, in citiesand on highwaysday andnight. Aircraft andtrains addto the environmentalnoise scenario. In indust y, machineryemits high noiselevels and amusement center and pleasure vehicles distractleisure time relaxation. In comparisonto otherpollutants, the controlof environmentalnoise has been hamperedby insufficientknowledge of ig effectson humansand of dose-response relationshipsas well as a lack of definedcriteria. while it hasbeen suggested that noisepollution is primarily a "luxurynproblem for developedcountries, one cannotignore that the exposureis oftenhigher in developingcountries, due to bad planningand poor constructionof buildings. The effectsof the noiseare just as widespreadand the long term consequencesfor healttrare the same. In this perspective,practical action to limit and control the exposureto environmental noiseare essential.Such action must be basedupon proper scientific evaluation of availabledata on effects,and particularly dose-response ielationships. The basis for this is the processof risk assessmentas describedbelow. A lfjegy employedfor evaluatingthe impact of an exposureto noise, can suitablyborrow terminologyfrom the field of toxicology. The broadintegrated processof risk assessment,is describedby the following elements: - Dosedescription: the level of the agentmust be describedin a way that is appropriatewith regardto the effectsobserved. & Health effects of environmental noise - Hazud identification:this is the qualitativeindication that a substanceor condition may adverselyeffect humanhealth or well being. It may representa very wide assessmentof possiblerisks. - Hazard assessment:the qualitativeand quantitativeevaluation of the nature of adverseeffects and their expressionas functionsof exposure(dose). - Risk estimation:the integrationof hazardassessment and dose description to quanti! the risk to be acceptedby the community(gpidelines, threshold values). nHazard"thus signifiesthe potentialof a specificagent to causeharm, and is an inherentproperty of the agentper se, in termsof its toxicity. "Risk" represents the quantitativestatement of the probabilityof occurrenceof a definedadverse effect. Dose description Soundis a wavemotion which occurswhen a soundsource sets the nearest particlesof air into motion. The movementgradually spreads to air particles further away from the source. Soundtravels through the air at a speedof approximately340 m/sec. The physicalmeasuring unit is the soundpressure in Pascal@a). The audiblesound covers a largerange of intensitiesfrom 0.00002 Pa at the thresholdof hearingto 20 Pa at the thresholdof pain. It would be impracticalto work with this large rangeof numbersand so an artificial unit has beencreated. The actualsound pressure is dividedby that for the thresholdof audition,followed by a logarithmictransformation. This unit, calledthe Bell @), is divided into tenthsand d(eci)B is the commonway to describea sound. Noisefrom differentsources combine to producea soundlevel higherthan that from any individualsource. Two equallyintense sound sources operating together,produce a soundlevel which is 3 dB higherthan one aloneand 10 ' sourcesproduce a l0 dB highersound level. The dB valuescannot be directly addedas they arelogarithmic quantities. Apart from the physical intensity, soundcontain many tonesat different frequencies.The soundwave's frequency expresses the numberof vibrationsper secondin units of Hertz (Hz). Soundexists over a very wide frequencyrange. Audible soundfor youngpeople lies between20 Hz md 20 000 Hz. Soundwith frequenciesunder 20 Hz (normally inaudible)is called infrasoundand soundover 20 000 Hz, which is alsonormally inaudible, is calledultrasound. Low frequency soundsare not strictly defined- generallyone refersto frequenciesfrom 20 to 25H2. 65 Motor vehicleair pollution when measuringthe intensity of a sound,an instrumentwhich duplicatesthe varying sensitivity of the ear to the soundof different frequenciesis usually used. This is achievedby building a filter into the soundintensity recording instrument, with a similar frequencyresponse to that of the ear. This is called an A-weighted filter. Measurementsof soundlevel madewith this filter are called A-weighta:l soundlevel measurements,and the unit is dBA. The dBA levelsfor some conmon noisesin our environmentare shownin Table 1. Table 1. Approximatenoise levels in dBA from commonnoise sources Sources I.evel Closeto jet engine 130 Rock drilling machine t20 Pop concert 110 Heavy truck 90 Passengercar 75 Normal conversation 65 Quiet suburbanstreet 55 Thresholdfor sleepdisturbance 45 Very quietroom 30 'Uncomfortably" quiet 15 Hearing thre,shold 0 In addition to the abovedescribed frequency-weighted filter, more complicated measureshave beendeveloped to describethe humanresponse to a complex sound. one suchunit is the PerceivedNoise Level (pNL) which is basedon frequency-weightedsound levels measured in successive0.5 secintervals during the occurrenceof a sound. Different soundspectra for noise rating have also bien developed.The soundspectrum curves, Noise Rating (NR) curves,serve as a frame of referencefor rating noise environments. NR curveswere originally ffi Health effects of environnental noise evolvedfor the rating of outdoor communitynoise and are presentas an ISO- recommendation(SO, 1971). From an acousticalpoint of view, environmentalnoise is often a complex phenomenon.This is illustratedfor roadtraffic noisein Figure 1. At a specific site alonga road, the noiselevel varieswith time dependingupon the type of vehiclethat passes.With a smallnumber of vehicles,the noiselevel will return to backgroundlevels between passages, whereas a largernumber of vehicleswill turn the exposuresituation into one of almostcontinuous noise, fluctuating befween the levelsgenerated by particularlynoisy vehicles such as trucksand the lower leveis generatedby cars. This complexacoustical pattern is by traditionexpressed as the summationof soundenergy over a certainperiod of time. Variousmethods of calculatingan averagehave been developed, such as the noisepollution level, the averageday and night level and the equivalentsound level for 24-h (L*) or different parts of the day. Anothermethod is the useof the statisticaldistribution level suchas the Lor, Lro or L5omeasures, which are alsobased on an averagevalue of eventsand noiselevels, but wherethe indexrefers to the time that the specificnoise level is reachedeg Lro is the level during l0% of the measuringperiod. For a complete review of all noiseindices the readeris referredto handbooksor criteria documents(for exampleWHO, 1980). The conceptof averagelevel has two critical features. A few eventswith a high noiselevel will havethe sameL* as a largenumber of eventsat a lower noise level. From a biologicalpoint of view, it is unlikely that thesetwo noise scenarioswill causean equaleffect in the exposedpopulations. A secondcritical featurefor the averagenoise value relates to the numberof events. If the L", value for a certain numberof cars at a certain distancefrom the road is, for example,65 dBA, then at that distancepassing cars will eachcause a maximumnoise level of 65 dBA andfew noisytrucks will reach75 dBA. If the numberof carsincreases, the L.o valuewill graduallyincrease, although the noiselevel from eachpassing car is still 65 dBA and75 dBA from a singletruck remainsthe noisiestevent. Under extremecircumstances, this may evenimply 67 o q o k Y rH k a c) bo Health effects of environmentalnoise that the L", value of 65 dBA is presentat a site, far away from the road where the noiselevels from individualvehicles, even very noisyones, is very low @igure2). The critical factor in the situationdascribed above is the numberof events. To what extentthen is the numberof eventsrelated to the human perceptionof environmentalstimuli? ffi 75dB(A) 10 000vehicle" '_ 5'^' 65ciB(A) \ r"c= 65 dB(A) \ z df,n+ L"q=74 dB(A) / 75dB(A) Boooo".:" AffiF .ffi 65dB(A) Figure2. L*and maximumnoise levels from cars-a #;m two different numbersof vehicleswith the sameproportion of trucks Biologicalreceptor systems (hearing, seeing, feeling, etc) are designedto discriminatefor variationsin the exposure.At a largenumber of events, however,the individualevent can no longerbe discriminated(for instance, flickering of light or applyingpressure on the skin with high frequency). It is thus plausiblethat an increasein the numberof noiseevents above a certainnumber, will not lead to an increasedeffect in the exposedpopulation. Regardingnoise exposure over a longertime period,Yaniv andvon Gierke(L974) suggestedthat the cumulativenoise dose, which an individualor a population sustainsover a lifetime couldbe usedto describethe biologicallyrelevant noise exposure.It is very questionablewhether this approachis relevant. The concept of a cumulativedose is valid only whenthe activeagent accumulates in the body, as, for example,does cadmium or asbestos,or whenthe exposureinflicts cumulativeand irreparabledamage, such as ionizingradiation or silicaparticles. 69 Motor vehicleair potrlution Noisearouses the receptororgans, not throughthe total amountof energy,but throughenergy density per unit of time - intensity- combinedwith frequency characteristics.Furthermore, the major part of humanreactions after exposureto environmentalnoise stems from the momentaryinterpretation of the noise. An exampleis tl.e intensefright reactioncaused by noiseof an unknowncharacter - which canbe of a very low level - occurringat night. On the otherhand, the comparativelyhigh noiselevel of a passingtrain canbe experiencedwithout any adversereaction at all. From a biologicalpoint of view, it is thusunlikely thatthe adequatehuman noise doseis eitheran averageexposure over a time periodor an accumulationof the noiseexposure. A biologicallyrelevant dose should be basedon neurophysiologicalreceptor principles and thusprobably comprises certain of the noiseevents, excluding others without biologicalsignificance, as well as the level oftheseevents. Hazard identification Noisemay causephysical, physiological and psychological effects in humans. The soundwaves will act physicallyagainst the eardrum with subsequentrisk for damageor interferencewith other sounds. Theseeffects may be referredto as direct effects. Throughthe nerveimpulse to the cenualnervous system, noise may induce physiologicalchanges and may finally registercognitively and causepsychological damage.These effects are referredto as indirecteffects. The effectthat vre measurein the exposedhuman may be a discretephysiological reactionor a complexreaction, such as sleepdisturbance or an effecton performance.For all effects,ttrose appearing after a singleor rare exposureas well as thoseoccurring after repeated exposures (chronic exposure) need to be considered. Hazard assessmentand risk estimation Fhysical efferts Noiseof a high enoughintensity wiil causetemporary or permanentdamage to the hearingorgan. The mechanismsbehind these injuries are well understoodand dose-rasponserelationships for continuousas well as intermittentexposure,. have beenpresented. With respectto enyironrnentalnoise and road traffic noise, no risk for hearingdamage exists. Levelsin the generalenvironment do not reach 70 Health effects of environmental noise thosewhich will inducehearing damage, even close to the traffic alongheavily congestedstreets. The interactionof noisefrom roadtraffic with other soundsin the environmentis an importanteffect criterion. Levelscausing speech interference are oftenpresent outsideand alsowithin buildingsclose to heavilycongested roads. Vulnerable groupsin the populationare schoolchildren in noisy classrooms.One study (Cohenetal., L973)has evaluated the influenceoftraffrc noise- relatedto speech interference- on the readingability of childrenin New York. It foundthat c.hildrenliving on the lower floors - andhence exposed to more roadtraffic noise - showedgreater impairment of auditorydiscrimination and reading achievement thanchildren living on higherfloors. Peoplewith hearingdeficiencies are alsoa risk group. Anianssonet al. (1983) studiedspeech interference, annoyance, and changesin moodin groupsof people with differentdegrees of hearingdeficiency and exposedthem to 45 dBA and55 dBA traffic noisein a laboratorywhen performing four everydayactivities. The major finding was a higherrating of annoyanceamong men with noise-induced hearingloss, as comparedto menwith normalhearing. This wasrelated to activitiesin which noiseinterfered with speech.To achievegood speech intelligibility for personswith impairedhearing due to ageand/or noise the authorsrecommended that the noiselevel outdoorsshould not exceed50 dBA (Anianssonand Peterson, 1983). This valuetook into accountthe reductionof noiseby about25 dB betweenoutdoor and indoorlevels, generally present in Scandinaviancountries. Physiological effects The immediateresponse to a noisestimulus comprises a startleand a defense reaction. The startleresponse is a reflex with contractionof musclesaround the eyes,in the limbs andthe eyelids(fhackray, 1972). It causesan attachmentof consciousnessto the noiseand its source,often followedup by an orientation towardsthe noisesource through involuntary muscular movements. This is a typical reactionwhich occursafter exposureto unexpectedor suddennoises, irrespectiveof their physicalnoise level. After an interpretationof the noisein the highercenters of the brain, a defenseand fright reactionmay follow. The startlereflex is a accompaniedby an increasein blood pressureand pulse frequencyof a very shortduration (up to 30 seconds),and in extremesituations, an increasedsecretion of stresshormones. 7l Motor vehicle air pollution Habituationto the startlereflex is very poor and canbe inducedrepeatedly both over the sameday as well as during longertime periods@ylander et d., 1978). In environmentalnoise, such reactions will occur if noiselevels exceeding the "normal" level appearfor instancewhen a motor cyclewithout silencersdrives down a road, a heavytruck comesthrough in the middleof the night or an unusuallynoisy aircraftpasses over the house. Basedupon observations of an increasein bloodpressure after acuteexposure to noise,it hasbeen suggested that long term exposureto noisecould causea persistentincrease in bloodpressure. Althougha seriesof experimentson animalssupports this concept(M6ller, 1978), the interpretationof resultsfrom animalsstudies presents difficulties. It is not surprisingthat rats, which are nocturnalanimals and very sensitiveto noise,when exposedfor 8 hoursdaily to 90 dBA, developpersistent stress reactions with elevatedblood pressure. Somediffrculties in interpretationcould be avoidedby usingother animalmodels, suchas monkeys@eterson et al., 1981). It is still not possibleto determinewhat kind of abnormalstress factor the experimentalnoise represents to the animal. If humanswere exposedto criesfrom peoplein agonyor nails scratchingover the surfaceof a blackboardfor severalhours each day, profoundclinical reactions would probablydevelop. The relevanceof sucha finding to exposureto environmentalnoise, however, remains obscure. To further evaluatethe relationshipbetween noise exposure and blood pressure, one canexamine the experiencefrom epidemiologicalstudies. Suchstudies on noiseexposed populations are relatively few, andall havebeen prevalence studies; no longitudinalinvestigations have been reported. The resultsfrom somestudies showa slightlyhigher blood pressure:rmong people living alongroads with heavy traffic as comparedto thoseliving in quietareas (Knipschild and Sall6, 1979). A review of the cardiovasculareffects of noisereported that 55 studieshad assessedthe relationshipbetween noise and blood pressureand about80% reportedsome form of positiveassociation @ejoy, 1984). Theseauthors noted that "a paucityof quantitativedata ... makesit difficult to assessthe strengthof associationor to derivea dose-responserelation". In a studyon the effectsof industrialnoise on the prevalenceof hypertension,Yiming et al. (1991)studied a groupof 1101female workers in a textile mill in Beijing, china. Essentially,the entiregroup had workedin differentworkhops in this mill for all their working lives and all had workedfor at leastfive years. The noiselevels within the plant were assessedand appearto havebeen constant since 1954, resulting in well definednoise exposures for theseworkers. A crosssectional design was used in 72 Heglth effects of environmental noise which blood pressureswere determinedand questionnaires administered to the workersover a two monthperiod. As well as demographicinformation, data weregathered on personaland family historyof hypertension,current use of prescriptiondrugs, alcohol, tobacco, and salt in the diet. Logisticregression indicatedthat exposureto noisewas a significantdeterminant of prevalenceof hypertension,but third in orderof importancebehind family history of hypertensionand use of salt. Cumulativeexposure to noisewas not an important dose-relatedvariable, suggesting that for thosesusceptible to the effect, hypertensionwas manifestedwithin the first five yearsof exposure. At present,the informationon the relationshipbetween environmental noise exposureand persistent blood pressureelevation is scantyand contradictory.It canbe arguedthat, althoughstudies on industrialpopulations are usefulinasmuch asthey includethe upperpart of the dosescale, they arenot representativeof noiseexposure conditions in the generalcommunity, particularly at homeduring hourswhen rest andrecreation are required. The few studieson generalpopulations that havebeen done, have serious epidemiologicalshortcomings. This is due in particularto the diffrculty in controllingfor confoundingfactors. The main risk factorsfor increasedblood pressureare other environmentalconditions, particularly food habitsand smoking, as well as geneticfactors. Noiseexposure therefore, is a low risk agentand this makesit difficult to investigatemethodologically. In studieson evaluationof low risk agents,there is a needto controlvery preciselyfor the high risk factors, beforeany certainconclusions regarding low risk factorscan be drawn (Wynder, 1987). In noneof the epidemiologicalstudies so far, hasthis methodological requirementbeen met. If a persistentincrease in bloodpressure is inducedby environmentalnoise, it is likely that it is modulatedthrough the basicreflex functionsdescribed earlier. This effectcould not be large,and it would be diffrcult to distinguishthe influence of noisefrom other environmentalstress factors, which couldalso produce a slight increasein bloodpressure. Sleepdisturbance Exposureto noisecan induce disturbance of sleepin termsof difficultyin falling asleep,alterations of sleeprhythm or depth,and being woken up. An objective recordingof sleepcan be obtainedby measuringthe electricalactivity of the brain, the electroencephalogram(EEG). This requiresthat subjectscarry several electrodeson their headsand that they are connectedto a recordingdevice, either directly or via telemetry. 73 Motor vehicle air pollution Thereexists an abundanceof informationon EEG-recordedsleep in laboratory andfield conditions.There is a fairly uniform consensusthat changesin sleep depth and sleeppattern are acuteeffects after exposureto noise at levels of 45-50 dBA peaklevels. A goodexample of a sleepstudy is an investigationfrom Francein which sleepdisturbance was studiedamong a populationliving neara railway anda major road (Vernet,1979). Two areaswith similar noise exposureswere selectedand ten personsof both sexeswere studied in eacharea. Sleeppatterns were registered using EEG andEMG (electromyogram)recordings, transmittedto a mobilevan outsidethe subjects'homes. A goodcorrelation was found between EEG definedsleep disturbance and peak noiselevel, but no correlationwas found between the durationof noiseand sleep disturbance.The percentageof responsesincreased when peak noise levels increasedabove 45 dBA. Subjectswere not wokenup by noisebelow 52 dB peak level. About25% of noiseevents at 70 dBA causedsleep interference. There werethree times as manydisturbances by roadtraffrc noiseas by railway noise for the sameL* value (meannoise level). Recordingof body movementshas also been used to studythe effectsof sleepand goodcorrelations have been found betweenEEG changesand actimetryreadings (wrist movementstransmitted from a sensorto a recordingdevice, about the same sizeas a largewristwatch). Availableinformation demonstrates ttrat noise exposure induces changes in sleep patternor causesextra body movements.Considerably less information exists on the medicalconsequences of disturbedsleep. Long term effectsof noiseinduced sleepinterruption could be subjectivefatigue, changes in performanceand subjectivemood changes. In laboratorystudies (Ohrstrdm et al., 1988),the effectsof truck noiseof maximum60 dBA werestudied during a periodof two weeksin order to illustrate habituationeffects on body movementsand heart rate, as well as after-effectssuch as subjectivesleep quality, stateof mind and performance.Two differenttest groups consisting of 24 personsin all - sensitive and non-sensitiveto noise- werestudied. Their sleepwas alsoregistered in their homesduring one weekbefore and one weekafter their stayin the laboratory. After two nights,sleep quality was just as goodin the laboratory. The studyshowed an increasein heartrate by an averageof 1.8 beatsper minute for sensitiveand 1.1 beatsper minutefor non-sensitivepersons following the noise events,and aboutthree times as manymovements after noisefor sensitivepersons againstan increaseof 2.5 timesfor non-sensitivepersons. These reactions showed no sign of habituation.Subjective sleep quality was impairedfor the sensitive groupand had not improvedat the endof the two-weekperiod. Both groups exhibitedreduced activity. This impairment(significant for non-sensitivepersons) 74 Health effects of environmental noise was still thereat the endof the testperiod. Moreover,an increasein fatigue (mostlyin the non-sensitivepersons) and a reduceddegree of extroversion(mostly for the sensitivepersons) could be registeredtowards the endof the periodof noiseexposure. Both groupsperformed worse in performancetests, and this deteriorationtended to continuetowards the endof the period. On the basisof experiencefrom thesestudies, a field studywas carriedout close to a road with heavytraffic (L* approx. 71 dBA) and in a quiet areafar from the road (L* approx.50 dBA) in order to studythe long-termeffects of noise exposureduring sleep(Ohrstr6m, 1989). The studycomprised a total of 106 persons,who were interviewedabout sleep quality, fatigue,mood, andvarious medicaland psycho-social symptoms. They werealso asked separate questions aboutsleep and mood on threesuccessive days. The studyshowed a deteriorationof sleepquality, moodand a higherfrequency of other symptomssuch as tiredness,headache and nervous stomach in the areaclose to the road with heavytraffic. Thosewho describedthemselves as sensitiveto noisereported poorer sleep quality and more symptoms. Amongpersons living alongnoisy roads, instant improvements in subjectivesleep quality.havebeen reported when windows were noise-insulated (Wilkinson et al., 1980;Ohrstrdm and Bj Studieson sleepinterference due to noiseagree that the mostimportant exposure parameteris peaknoise during night hours. As effectsare generallyreported at levelsfrom 45 dBA peaklevel indoors,large parts ofthe populationin our cities arethus regularlyexposed to noiselevels which interferewith their sleep. ln conclusion,available evidence suggests that sleepdisturbance is oneof the major effects of environmentalnoise and that it may have seriousadverse effects on normalfunctioning and health in exposedpersons. Psychologicaleffects It is commonknowledge that noisecan be bothersomeand give rise to psychologicaland psychosomatic symptoms in the form of headaches,fatigue and irritability. Biochemicalreactions indicating a generalstress effect of noisehave alsobeen reported from animalsand hurnan studies (Cantre!!, 1974). In view of the informationavailable on the stressreaction occurring after noise exposure,as well as sleepdisturbance, psychiatric symptolns or disordershave receivedparticular attention.' Psychiatric effects could occur in threedifferent ways: symptomscould develop among previously normal persons, their 75 Motor vehicle air pollution developmentcould be acceleratedin predisposedpersons or symptomscould appeartemporarily under particular conditions. No dataare availableon psychiatricdisease and road traffic noise. Somestudies on aircraftnoise have been published. Epidemiologicalevidence for a relationship betweenaircraft noise exposure and psychiatric illness was presented by Abey- Wickramaet al. (1969). They describedan increasedadmission rate to psychiatric hospitalsamong a populationliving in an areaexposed to high levelsof aircraft noise. This observationprompted additional studies which employedmore precise epidemiologicaltechniques. A subsequentstudy by Ganoniand Tarnopolsky (1973)did not confirm Abey-Wickrama'sfindings. A further studyby Jenkinset al. (1979)on psychiatrichospital admission rates in the samearea over a 4-year period alsofailed to demonstratea higheradmission rate amongnoise exposed persons. The latter authorsmade a carefulanalysis of possiblere:xons for the contradictory resultsand convincinglydemonstrated the variousshortcomings in the first study which couldhave accounted for the observedincrease in admissionrate observed in noiseexposed areas. It canthus be statedthat no epidemiologicalevidence is at presentavailable which indicatesthat thereis an increasedrisk for psychiatric disordersamong general populations exposed to noise. In anotherstudy on the effectof aircraftnoise on mentalhealth, Tarnopolsky and Morton-Williams(1980) investigated 6,000 persons living in areaswith different levelsof aircraftnoise exposure. The surveycovered four areasin Londonwith differentlevels of aircraftnoise exposure, and the subjectsanswered questionnairesrelating to generalhealth, psychiatric illness and annoyance.Of the noiserelated effects, depression, irritability, awakeningsand diffrculty in falling asleepwere significantlymore frequentin the high noisearea. The prevalenceof symptomswas significantlyhigher among persons who expressedthat they were annoyedby the noise. Therewas no relationshipbetween the numberof possible psychiatriccases and noiseexposure. No increasein consumptionofpsychotropic drugsor useof medicalservices was found in the high noisearea. It couldbe hypothasizedaccording to previousstudies on noiseeffecg (e.g. Ohrstrdm,1989), that physicaland psycho-social symptoms and reduced work capacitymay occur as an effect of generalannoyance and sleepdisturbances causedby noiseexposure. These symptoms may, of course,also be dependent uponother circumstances,for examplechronic illness, difficulties in the family situationor work conditions.The individualcapacity to handlestress might also be of importancein the developmentof differentsymptoms. 76 Health effects of environmental noise Ohrstrdm(1991) performed a field surveyin a quietarea and an areaexposed to an L*-level of 72 dBA to elucidatepossible psycho-social effects of roadtrafhc noise.-A questionnairewas constructedto evaluatenot only annoyancereactions andsleep disturbance effects by noise,but alsomore long-termeffects on psycho- socialwell-being @SW). PSW wasevaluated by 26 questionsconcerning depression,relaxation, activity, passivity,general well-being and social orientation. The postalquestionnaire was answeredby 151persons in the quiet areaand 118persons in the noisy areaof which 97 lived in apartmentsfacing the streetand 21 personsin apartmentsfacing the courtyard. The resultsshowed that a higherproportion of thosewho lived in the noisy areain apartmentswidl windowsfacing the streetfelt depressed.Those persons who had windowsfacing the courtyard,in the noisy area,however, were not moredepressed than those who lived in the quietarea. Psycho-socialwell-being (especially depression and relation)was related to annoyanceabout noise. The resultsavailable so far, do not indicatethat environmentalnoise provokes psychiatricdisease. Noise may, however,act as a stressor,inducing symptonx amongsensitive individuals. The exactconditions under which theseindividuals becomevulnerable are not known, but it is conceivablethat other environmental strainscould act synergisticallywith noise. Annoyance Exposureto environmentalnoise may interferewith ongoingactivities and canbe experiencedas bothersomeor annoying. Annoyanceis generallydefined as a feelingof displeasureagainst a sourceof pollutionin the environmentwhich the individualknows or believeswill adverselyaffect his healthor well-being. As the annoyanceis a subjectivereaction, it hasto be evaluatedusing questionnaire techniques. Whenthe relationshipbetween noise level andthe degreeof individualannoyance is evaluated,it is generallyfound that the noiseexposure can explain only part of the total reaction. Onereason for this is that the noisedose of the individualis not preciselydefined - in socialsurveys, persons living in a specificarea are usuallyallotted the areaexposure value. Anotherrquon is variationsin individual sensitivity. The inter-individualvariation of an effect- in this case,annoyance - causedby an environmentalagent is not surprising. Reactionsto any type of agentvary :rmong individuals,whether the agentbe noiseor a chemicalsubstance. The same methodologyas is usedin toxicologymust therefore be applied,i.e. working with averagereactions in groupsof persons. 77 Motor vehicle air pollution A largenumber of studieshas been performed to evaluatethe relationshipbetween exposureto roadtraffic noiseand the extentof annoyancein the exposed populations.Based upon methodology originally developed to studythe effectsof aircraftnoise, large investigationsin roadtraffic noisewere performed in London by Langdonet al. (1976),followed by a plethoraof studiesin other countries. It is not within the scopeof this paperto providea completereview of all studies performed. Apart from the noiseexposure principles, to be discussedbelow, thereis relativelylittle controversy:ts regardsthe importanceof the exposureand the different effects. The studiesagree that exposureto roadtraffic noiseis oneof the mostimportant sourcesof annoyancein the generalpopulation. The numberof personsaffected far exceedsthe numberdisturbed bv aircraftnoise or other environmentalnoise sources, Regardingmethods of expressingexposure to roadtraffic noise,controversy still existsas mentionedabove. Many studieson roadtraffic noisedemonstrate a faidy linear correlationbetween the equivalentnoise level andthe extentof annoyance (Langdon,1976; Fidel, et al., 1991)but other studiesshow a poor correlation (Rylanderet al., 1986). A betterrelationship between the extentof annoyanceand noisewas obtainedif the noiselevels and number of eventswere treated separately.An increasingnumber of eventsinitially causedan increasedextent of annoyancebut beyonda certainpoint, a further increasein the numberof events did not influenceannoyance. The maximumnoise level (MNL) determinedthe extentof annoyanceirrespective of the numbersof events(Rylander et al., 1972; Bjrirkmanet al., 1988). It is clearthat in conditionsof continuousnoise, there is very little to distinguish betweenthe equalenergy concept and the MNL concept. This may be one of the rsuons why severalstudies on roadtraffic noisehave been able to showa statisticallysignificant relationship between noise exposure (as average noise levels)and the extentof annoyance. The few studiesthat havebeen performed with the aim of studyingthe importance of the numberof events,the noiselevels and the maximalnoise levels as independentvariables, have all cometo the conclusionthat the relationship betweenL* for traffic noise and the effect, whetherthis be annoyanceor sleep disturbance- in the exposedpopulation is weak. As an exampleGjestland (1987) re-evaluated data from a Danishtraffrc noise studyand performed a small laboratoryexperiment in which he exposedsubjects to traffic noisewith differentlevels of heavytraffic. The synthesisfrom his work suggeststhat the effectsof a reductionin the numberof heavyvehicles was much 78 Health effects of environmental noise more effectivethan a generalnoise attenuation. He concludedthat the L". as a noiseindex often fails to describeirregular noise situations. The noisiestevents in roadtraffic are generallyfrom heavyvehicles. There are severalrqsons why the numberof heavyvehicles should be closelyrelated to the extentof annoyance.The noiselevels from heavyvehicles are cleady distinguishablefrom a backgroundof lower levelsfrom passengercars. Also, the noisefrom heavyvehicles has a differentacoustical character, mostly in the low frequencyspectrum. The effectof window attenuation,which in generalis poor for low frequencies,will give proportionallyhigher noise levels indoors from, the heavyvehicles. Conclusion The rangeof effectsinduced by exposureto roadtraffic noiseis wide and covers simplereflex as well as complexpsycho-social effects. The mostserious adverse effectis sleepdisturbance with its long term consequencesfor healthand well- being. Annoyancedue to environmentalnoise is widespread,particularly in built up arqN and aroundairports. It is an importantcriterion for noiseexposure and canbe usedas the basisfor establishingnoise control programs. Accordingto the definitionof healthgiven by WHO, subjectiveannoyance should be consideredan importanthealth effect. The medicalrationale, therefore for takingaction against noise exists. A practical meansto confrontthe problemis to makethe subjectiveinterpretation of noisethe primary criterion,and back this up with informationon doseresponse relationshipswhich havebeen established. Noisestandards should relate to the extentof the effecton the population,i.e. what proportionofthe populationsuffering from serioussleep disturbance can be consideredas acceptable.According to the principlesof risk assessment,the settingof suchstandards is not in the handsof scientists- it is the responsibilityof administratorsto chooseacceptable levels. Medicaleffect data constitute the necessarybackground information for the formulationof thesestandards. A long term goal from a medicalpoint of view is that the proportionof very annoyed peoplein a population,in built-up areas,should not exceeASVo. 79 Motor vehicle air pollution The following are importantresearch questions to answerin the future: - Is therea relationshipbetween annoyance and physiological/clinical effects? some evidenceindicates that this is the casefor psychiatricsymptoms, but more work is required. - How does interruption of different mentalactivities relate to physiological/clinicaleffects and to generalannoyance? - Are activity interference,annoyance reactions and performanceeffects all secondaryreactions to, or symplomsof, noiseinduced physiological stress? 80 Health effects of environmental noise REFERENCES Abey-Wickrama,I. et al. Mentalhospital admissions and aircraft noise. Lancet, 2: 1275-1277(1969). Andr6n,L. et al. Noiseas a contributoryfactor in the developmentof elevated arterial pressure. Acta Medica Scandinavica,207 : 493498 (1980). Aniansson,G. et al. Traffrc noiseannoyance and noisesensitivity in personswith normaland impairedhearing. JournalofSound Vibration,83: 85-97(1983). Aniansson,G. & Peterson,Y. Speechintelligibility of normallisteners and personswith impairedhearing in traffrc noise. Journal of Sourd Vibraion,90: 341-360(1983). Cantrell,R.W. Prolongedexposure to intermittentnoise: Audiometric biochemical,motor, psychologicaland sleepeffects. lnryngoscope,Suppl 1, 84, Pt2 (1974). Cohen,S. et al. Aircraft noiseand children:Longitudinal and cross-sectional evidenceon adaptionto noiseand the effectivenessof noiseabatement. Journal of Personalityand SocialPsychology,40: 330-345 (1973). Dejoy, D.M. A reporton the statusof researchon the cardiovasculareffects of noise. NoiseControl Engineering J ournal, 23: 32-9 (1984). Drettner,B. et al. Cardiovascularrisk factorsand hearing loss. ,{cta Oto-laryngologica,19: 36f,.37L Qn 5. Fidell, S. et al. Updatinga dosage-effectrelationship for the prevalenceof annoyancedue to generaltransportation noise. Journal ofthc AcousticalSociety of America,89:221-233 (1991). Gattoni.F. & Tarnopolsky,A. Aircraft noiseand psychiatric morbidity. Psy cholo gical Medicinc, 3 : 5 16-520(197 3). Gjestland,T. Assessmentof annoyancefrom roadtraffrc noise. Jounwl of Sound Vibration, ll2: 369-375 (1987). Jenkins,L.M. et al. Comparisonof threestudies of aircraftnoise and psychiatric hospitaladmissions conducted in the samearca. PsychologicalMedicine. 9: 681- 693 (1979). 8l Motor vehicle air pollution Knipschild,P. & Sall6,H. Roadtraffic noiseand cardiovasculardisease. A populationstudy in the Netherlands. InternationalArchives of Occupationnland EnvironmcntalHealth, 44: 55-59 (1979). Langdon,F.J. Noisenuisance caused by roadtraffic noisein residentialareas: Part I. Journal of SoundVibration,4T:243-263 (1976). Langdon,F.J. Noisenuisance caused by roadtraffrc noisein residentialareas: Part II. Journalof SoundVibration, 47: 265-282(1976). M0ller, A. Reviewof animalexperiments. Journal of SoundVibration,59:73- 77 (t978). Ohrstrdm,E. & Bjdrkmil, M. Sleepdisturbance before and aftertraffic noise attenuationin a block of flats. Journalof the AcousticalSociety of America,T3: 877-879(1983). Ohrstrdm,E. & Rylander,R. Sleepdisturbance effects of traffic noise- A laboratorystudy on after effects. JournalofSound Vibration,34: 87-103(1982). Ohrstrdm,E. Sleepdisturbance, psycho-social and medical symptoms - a pilot surveyamong persons exposed to high levelsof roadtraffrc noise. Journal of SoundVibration, 133: lt7 -128(1989). Ohrstrdm,E. Psycho-socialeffects of traffrc noiseexposure. Journal of Sound Vibration,(in press)(1991). Ohrstrdm,E. et al. Effectsof night time roadtraffic noise- an overviewof laboratoryand field studieson noisedose and subjective noise sensitivity- Journal of SoundVibration, 127: 441448 (1988). Peterson,E.A. et al. Noiseraises blood pressurewithout impairingauditory sensitivity. Sciences,2Ll:. 1450-1452(1981). Rylander,R. et al. Experimentson the effectof sonicboom exposure. Journal of the AcousticalSociety of America, 5L 790-798(1972\. Rylander,R. et al. Annoyancereactions from aircraftnoise exposurc. Journol af SoundVibration,24: 4L94M (1972). Rylander,R. et al. Dose-responserelationships for traffic noiseand annoyance. Archivesof EnvironmentalHealth, 4l:7-10 (1986). 82 Health effects of environmental noise Rylander,R. & Dancer,A. Startlereactions to simulatedsonic boom exposure: influenceof habituation,boom level andbackground noise. Journal of Sound Vibration,6l: 2354$ (1978). Tarnopolsky,A. & Morton-Williams.J. Aircraft noiseand prevalence of psychiatricdisorders. Socialand CommunityPlanning Research Repoft, pp. 1-80 (1980). Thachray,R.I. Sonicboom exposure effects: Startle responses. Journal of Sound Vibration,20: 5 L9-526 (197 2). Vernet,M. Effect of train noiseon sleepfor peopleIiving in housesbordering the railway line. Journalof SoundVibration,66: 483492 (L979). Wilkinson,R.T. et al. Effectsof noiseat night uponperformance during the day. ln: Proceedingsof the Third International Congresson Noise as a Public Health Problem,Freiburg, Germany, ASHA Reportsno 10: 405-412(1980). World HealthOrganization. Noise. Geneva,WHO, 1980@nvironmental Health CriteriaNo. 12). Wynder,E., ed. Workshopon guidelinesto the epidemiologyof weak association.Preventive Medicine, 16:. 139-212 (1987). Yaniv, S.L. & von Gierke,H.E. Methodfor the identificationof environmental noiselevels requisite to protectspublic healthand welfare. ln: Proceedingsofthe Internaional Symposiumon RecentAdvances in the Assessmentof the Heahh Effectson EnvironmentalPollution, Paris, pp. 1263-1216(1974). Yiming, Z. et al. A doseresponse relation for noiseinduced hypertension. British Journal of Industial Medicine,48: 179-184(1991). 83 CHAPTER 3 IITJMAN EXPOSURE TO MOTOR VEHICLE AIR FOLLUTANTS PeterG. Flachsbart' Introduction Humanexposure to air pollutantsoccurs whenever people come into contactwith a pollutantat a particularinstant of time (Ott, 1980). The dosageof a pollutantis the amountof pollutantthat entersthe body, eitherthrough inhalation, ingestion or dermalabsorption. Accurate estimation of air pollutionexposure and dosage are necessaryto determinewhat risk that pollutionposes to public health (Sextonand Ryan,1988). PeterG. Flachsbart,Ph.D. AssociateProfessor, Department of Urban andRegional Planning, University of Hawaii at Manoa,Honolulu, Hawaii 85 Motor vehicleair pollution Ambientair qualitydata from fixed stationshave been used to estimatethe risk that pollutionposes to pubichealth. Many studieshave found that while these stationsrepresent typical exposuresfor a largemajority of urbanpopulations, they do not adequatelycharacterize human exposure to certainprimary pollutantsfrom motor vehicleimpacted microenvironments, such as insidemotor vehiclesand alongroadsides (Ott andEliasson, L973). A microenvironmentexists for a pollutantif the concentrationof ttrepollutant at a particularlocation and time is sufficientlyhomogenous yet significantlydifferent from the concentrationsat other locations@uan, 1982). This chapterselectively reviews studies of humanexposure to air pollutantsfrom motor vehicles,such as evaporativefuel lossesand tailpipe emissions. The objectivesof this review are: (1) to describetypical levelsof humanexposure to motor vehicleair pollutantsin severalvehicle related microenvironments; and (2) to estimatehow manypeople are exposedto motor vehicleair pollutantsin these microenvironmentsin developedand developing countries. This chapterbuilds on literaturereviews undertaken by Flachsbartand Ott (1984),Flachsbart and Ah Yo (1989)and Ott et al. (1991b). Most of the studiesreviewed in this chapterhave focused on pollutantsdirectly emittedby vehicles,such as carbonmonoxide (CO), nitrogenoxides (NO), lead (Pb), and severalvolatile organic compounds (VOCs), such as benzene,m-/p- xylene,and ethylbenzene.A few studieshave looked at exposureto ozone(O3) which is createdin the atmospherefrom VOCs and NO* througha photochemical process. Typical Levels of Personal Exposure Estimatesof personalexposure to air pollutantsfrom motor vehiclesemploy either a direct or an indirectapproach. In the direct approach,personal monitors are distributedto a sampleof the population. As peopleengage in their regulardaily activities,they recordtheir exposureto selectedpollutants using the personal monitors. In the indirectapproach, trained technicians use personal monitors to me:tsureconcentrations in selectedmicroenvironments and then combinethis informationwith additionaldata on humanactivity patterns to estimatethe time spentin thosemicroenvironments. Direct Approach In the direct approach,subjects can record their exposuresin a diary, as wasdone in a pilot studyin Los Angeles(Ziskind et al., 1982),or exposuredata can automaticallybe storedin a datalogger, as wils donein studiesin Denverand Washington,D.C. (Aklandet al., 1985). Subjectsalso record the time duration 86 Human exposure to motor vehicle air pollutants andnature of their activitiesin specifiedmicroenvironments while monitoring personalexposures. The direct approachis usefulfor obtainingan exposureinventory, ideally of a representativesample, from eitherthe generalpopulation or from a specific subpopulation,which canbe definedby demographic,occupational and health risk factors. The inventorycan cover a rangeof microenvironmentsencountered over a periodof interest(e.9., a day), or it canfocus on oneparticular microenvironment.With this flexibility, healthofficials firn assessthe problem that motor vehiclespose to a particularsubgroup of the populationactive in a specificmicroenviroment, e.g., parkinggarage attendants. General Popul atio n St udies Direct studiesof the generalpopulation are rare becauseof their expenseand the logisticalproblems of monitordistribution. The bestexamples of suchstudies werethe Denver,Colorado and Washington, D.C. studiesof CO exposures (Aklandet al., 1985). In both studies,higher exposures were associated with commuting. The two highestaverage CO concentrationsoccurred when subjects were in a parkinggarage or parkinglot andwhen travelling. High exposures werealso traced to indoor andoccupational sources. The averageCO 'in-transit" concentrationsobserved for all microenvironmentsare shownin Table 1, basedon supplementarydata analyses by WayneOtt (Ott, Switzerand Willits, 1991b). Denverhad higher averages for eachmicroenvironment, because its colderclimate causes higher CO motorvehicle emissions. Table1. Typical In-VehicleCO Exposures(ppm) in Two U.S. Citiesin 1982-1983. In-Transit Denver,Colorado Washington,D.C. Microenvironment Mean SD n Mean SD Automobile 3029 7.8 11.3 3345 4.6 6.5 Bus 70 9.0 6.9 r67 3.5 5.9 Truck 350 7.2 9.5 135 5.3 8.1 Motorcycle 20 12.3 9.5 3 3.0 3.3 Subway 95 2.0 1.8 87 Motor vehicle air pollution In Denver,approximately 3 percentof the daily marimum l-hour exposuresof 454 studyparticipants exceeded 35 ppm, the l-hour U.S. NationalAmbient Air Quality Standard(NAAQS) for CO, andabour 11 percentof the daily maximum 8-hourexposures exceeded the 9 ppm NAAQS (Johnson,1984). In Washington, 1.3 percentof 7l2 subjectssurveyed had maximumhourly CO exposures exceeding35 ppm and about4 percentof the samplehad maximum8-hour exposuresexceeding 9 ppm (Hartwellet al., 1984). In both cities,the composite networkof fixed-sitemonitors overestimated the 8-hourpersonal exposures of peoplewith low level exposuresand underestimated the 8-hourpersonal exposures of peoplewith high exposures. C-ommuterStudies Two studiesfocused solely on commuterexposure to air pollutantsfrom motor velriclesusing the direct approach.Cortese and Spengler (1976) found that CO exposuresaveraged 11.9 ppm for 66 non-smokingvolunteers who commuted45 to 60 minutesone way in Boston,Massachusetts. Each volunteer wore a CO personalmonitor for threeto five daysover a six-monthperiod. Simultaneous measurementstaken at six fixed-sitemonitors averaged only 6 ppm. Shikiyaet d. (1989)collected samples of in-vehicleconcentrations of CO, two aldehydes,six halogenatedhydrocarbons and four metalsduring the peak commutinghours during summerand winter in metropolitanLos Angeles, california. The researchersselected a randomsample of 140nonsmokers who commutedfrom hometo work in privatelyowned vehicles during eachseason. Driving patternsand ventilation conditions were not controlled. Table2 givesthe averageconcentrations of vehicle-relatedorganic gases and metalsfor round-trip commutes.One-way-commuting collection time averaged33 minutesfor organic gasesand aldehydesand 52 minutesfor metals. Meanin-vehicle concentrations substantiallyexceeded mean ambient concentrations for all pollutantsexcept ethylenedibromide, chromium and lead. Ten yearsearlier, Dzubay, et al. (1979) reportedt{at the meanin-vehicle lead concentrationon Los Angelesfreeways was 10.9pgln3 for drivesof 2 - 4 hours. This wassix timesgreat-r thanthe mean ambientconcentration. The reductionin leadexposures observed by Shikiyaet al. (1989)corresponds to the mandatedreduction of leadfrom gasolinethat occurred during the periodbetween these two studies. Indirect Approach Exposurestudies that usedthe indirectapproach ars more numerousthan those that usedthe direct approach.some of thesestudies describe typical exposuresin specificmicroenvironments. Microenvironmental studies may try to replicate urbantravel by car or trips betweenhome and work by differenttravel modes, 88 Human exposureto motor vehicle air pollutants while othersfocus solely on the mostcongested portion of the trip wherevehicles are movingslowly dueto high traffrc volumesand/or constricted space. In either 'standardized" case,hypothetical routesare selectedto estimatetypical in-vehicle exposuresof commuters. Table2. Typical Concentrationsin Los Angeles,Californiain 1987- 1988. MeanIn-Vehicle MeanAmbient Air Pollutant Concentration Concentration OrganicGases Benzene 13.3ppb 5.3 ppb Carbonmonoxide 8599 ppb 3661 ppb Ethylenedibromide 0.014ppb 0.016ppb Ethylenedichloride 0.033ppb 0.010ppb Formaldehyde 12.5ppb 6.8 ppb Toluene 36.3 ppb 14.7 ppb Xylene 32.9 ppb 15.3 ppb Metals Chromium 0.012 pglnr3 0.023 pglm' Lead 0.218 pglnr3 0.208p,glm- More specializedmicroenvironmental studies have focused on in-vehicleexposures at high-volumeintersections and in vehicularwaiting lines. Othershave explored concentrationsin tunnels,underpasses, puking garagesand buildings attached thereto,service stations, and alongcurb-sides. In thesestudies, some have identifiedhigh levelsof exposurefor specificsubpopulations, while othershave evaluatedmeasurqs to mitigatehigh exposures.Several other studieshave tried to explainhow outdoorconcentrations affect indoor concentrations. Many other studieshave focused on factorsthat affectlevels of exposure,i.e., the covariates of exposure,such as trafFrcvolumes and speeds, vehicular self-contamination and ventilationand meteorological factors. The readeris referredto Flachsbartand Ah Yo (1989)for a review of covariatestudies, which arebeyond the scopeof this review. 89 Motor vehicle air pollution StandardizedRoutes Studiesof standardizedroutes have shown that fixed-sitemonitors underestimate in-vehicleexposures to someair pollutants,but over-estimatethese exposures for otherpollutants. Petersenand Sabersky (1975) reported that averagein-vehicle CO levelsin Los Angeleswere generally 15 - 20 ppm and weresimilar to concentrationsimmediately outside the vehicle. Fixed-sitemonitors showed maximumCO levelsof only 8 ppm. A later studyin Los Angelesby Petersen andAllen (1982)reported lower in-vehicleCO valuesof 10.9- 15.3ppm, which were 3.9 timeshigher than concentrationsat fixed-sitemonitors. Holland (1983)found that in four U.S. cities,urban residential, fixed monitoring stationsunderestimated the time-weightedmean of commutingand residentialdrivingexposures to CO over standardizedroutes by factorsof 0.4 to 0.7. Luria et al. (1985)found that CO concentrationsexterior to their testvehicle in Jerusalem,Israel were muchhigher than any levelsmeasured at fixed-site monitors. In Raleigh,North Carolina,Chan et al. (1991)stated that medianCO concentrationswere 11 ppm insidetest vehicles on standardizedroutes, but only 2.8 ppm at fixed-sitemonitors. Ott et al. (1991a)measured in-vehicle CO concentrationson 88 standardizedtrips over a one-yearperiod in 1980on a suburbanarterid highwayin the San FranciscoBay Area of California. They reporteda meanCO concentrationof 9.8 ppm for typicaltrips of 35 - 45 minutes;the medianCO concentrationswere only 1.0 ppm at the two nearestfixed-site monitors. Ott et al. (1991c)currently are resurveyingthis highwayusing a methodologysimilar to their previousstudy to determinein-vehicle exposure trends. Basedon preliminaryfindings, they reportedthat the meanin-vehicle CO concentrationhad droppedto about5 ppm or 51 percentof the meanvalue estimated 11 yearsearlier. They attributedthis exposurereduction to the replacementof older vehicleswith newervehicles that havelower emissionfactors. This reductionis particularlysignificant, as daily traffic volumeon this highwayhas grown by about17 percentduring the interveningperiod, accordingto estimatesby Hildemannet al. (1991). Chanet al. (1991)reported differences between measurements in vehiclesand at fixed-sitemonitors for severalVOCs, includingbenzene, ethylbenzene, hexane, isopentane,m-/p-xylene, n-butane, n-pentane, o-xylene, 1,2,4-trimethylbenzene, toluene,2-methylpentane, 2,3,3-trimethylpentane and 2,2,4-trimethylpentane. Weiselet al. (1991)found that in-vehicleVOC concentrationswere 3 - 10 times higherthan ambientlevels during 30-minuteidling periods. However,the mean concentrationsof severalVOCs while commutingwere lower thanthose found by Shikiyaet d. (1989)in Los Angeles,but similarto concentrationsmeasured by Chanet al. (1991)in Raleigh. 90 Human exposureto motor vehicle air pollutants Fixed-sitemonitors may overestimatein-vehicle exposures for other air pollutants relatedto motor vehicles. Petersenand Sabersky(1975) found that in-vehicle concentrationsin Los Angelesranged from 0.05 - 0.50 ppm for NO andfrom 0.24 - 0.80 ppm for NO' while ambientconcentrations of thesetwo pollutants were significantlyhigher at the nearestfixed-site stations. Similarly, ozone concentrationswere generally below 0.05 ppm insidethe vehicle,about three to four timeslower than in the ambientenvironment. Chan et al. (1991)observed a similar resultfor ozonein Raleigh,but Luria et al. (1985)found that NO* concentrationsexterior to their testvehicle in Jerusalemwere muchhigher than any levelsmeasured at fixed-sitemonitors. Studiesof standardizedroutes have also been used to assessthe effectivenessof priority (restricted)lanes for carpools,highoccupancy vehicles (HOVs), and expressbuses in reducingcommuter exposure to motor vehicleexhaust in Honolulu,Hawaii (Flachsbart,1989). In this study,in-vehicle exposure to CO servedas a surrogatemeasure of traffrc congestion,since higher CO emissionscan be associatedwith slowermoving trafhc. Comparedto commuterCO exposurein umestrictedlanes, exposure was about 18 percentless for thosein carpools,28 percentless for thosein HOVs, and6l percentless for thosein expressbuses. Commutersin priority lanesalso achieved speed advantages which partially explainedtheir reducedCO exposures. The last threestudies in this categoryare of particularinterest, because two were undertakenin a developedcountry and the other in a developingcountry and their methodsof datacollection were similar. Flachsbartet al. (1987)reported the time-weightedCO concentrationsfor three modesof travel in the Washington,D.C. metropolitanarea during winter 1983. CO concentrationswere measured during morningand eveningrush-hour periods on 15 hypotheticalcommuter routes: eight congested highway routes, four bus and threerail routes. Typical in-vehicleCO exposuresfor automobilesranged from 9 - 14 ppm for trips of 40 to 60 minutes. By comparison,typical CO exposures for transitusers were substantiallyless, ranging from 4 - 8 ppm for bustrips of 90 to 110minutes and 2 - 5 ppm for rail trips of 30 to 45 minutes. Wallace(1979) found similar differencesin car andbus commutesbetween Reston, Virginia and Washington,D.C. The Flachsbartet a!. (1987)study obser.red higher CO exposuresfor automobile commutesthan did Akland et d. (1985),even though both studieswere donein the samemetropolitan area about the sametime. This differencecould be explainedby a differencein studydesign. Akland et al. directly surveyeda representativesample, thereby capturing all typesof urbantravel throughoutthe day. Flachsbartet al. purposelyselected long commuterroutes over known 91 Motor vehicle air pollution congestedhighways during rush-hourperiods only. Thus,the Flachsbartet al. resultsmay be represenBtiveof commuterswith high levelsof exposure. Fernandez-Bremauntz(1992) monitored CO concentrationsinside various types of vehiclestypically usedfor commutingin the metropolitanarea of Mexico City, Mexico during winter months. Table3 reportsresults for 549 trips, representing r."combination of five differentcorridors, as dividedinto linls, andsix travel modesduring morningand evening commuting periods. BetweenOctober 1990 andFebruary 1991, the meandaily maximum8-hour ambient CO concentrations at four stationsin Mexico City rangedfrom 7 to 11.5ppm. Fernandez-Bremauntz generallyfound muchhigher exposures inside automobiles than insidebuses and subways,a resultsimilar to the abovefindings in Washington,D.C. Table3. Typical CO Concentrationsin Mexico City, Mexico in 1991. Rangein Mean Number Travel mode CO Concentrations of Trips Privateautomobile 55 - 57 ppm 34 'Combi" type van 39 - 67 ppm 35 Minibus 32 - 64 ppm t52 Dieselbus 20 - 40 ppm 170 Electrictrolleybus 22 -32ppm 47 Subwayand light rail 16-26ppm 111 The meanin-vehicle exposures for eachtravel modein Mexico City are much hrgherthan those in Washington,D.C. Most vehiclesin Mexico uselower quality fuels andgenerally have no pollutioncontrols. In fact, the Mexico City exposures are hlghel than exposuresobserved in the United Statespdgg to the adventof emissioncontrols there in 1968. For instance,Brice andRoesler (1966) measured in-vehicleconcentrations of CO andhydrocarbons while driving in moderateand heavytraffic from outlyingareas to downtownlocations in six U.S. cities. Table4 showstypical concentrationsfor 3O-minuteaveraging periods for each pollutant. 92 Human exposureto motor vehicle air pollutants Table4. Typical In-VehicleExposures in Six U.S. Citiesin 1966. CarbonMonoxide Hydrocarbon Concentration(ppm) Concentration(ppm) Mean Range Mean Range Chicago,Illinois 37 20-59 4.8 2.4- 8.4 Cincinnati,Ohio 2l 8-s0 5.7 3.6- 11.6 Denver,Colorado 40 22-72 9.6 4.6 - 19.0 St. Louis, Missouri 36 lt -77 9.3 4.4 - 19.0 Washington,D.C. 25 7 -43 6.2 2.0 - 23.0 Intersections Ramsey(1966) surveyed 50 intersectionsover a six-monthperiod in Dayton, Ohio. He reporteda strongrelationship between traffrc volumeand CO concentrationsat intersections.Concentrations ranged from 56.1 ppm (mean)I 18.4ppm (onestandard deviation) for heavytraffic to 31.4 t 31.5ppm for moderatetraffic to 15.3 + 10.2ppm for light traffic. He reportedthat concentrationswere greater at intersectionsalong major arteriessomewhat removedfrom downtownDayton, and that their meanconcentration was 3.4 times the meanof intersectionsa block awayand perpendicular to the axis of the arterial. Willits andOtt (1981)also found a statisticallysignificant linear relationshipbetween passenger exposure and traffic countsat congested intersectionson a suburbanarterial highway in northernCalifornia. Seifertand Abraham(1982) surveyed several VOCs at traffic intersectionsin West Germany. They reportedmean concentrations of 100pglm3 for mJp-xyleneand L47 pgtnf for toluene. Queues Myronuk (1977)measured CO concentrationsinside automobiles that were idling in queuesto a drive-upfacility in SantaClara Valley, California. The in-vehicle CO concentrationsranged from 15 - 95 ppm for l5-minuteaverages, with short term peaksbetween 100 and 1,000ppm. BackgroundCO levelswere only 2-5ppm. 93 Motor vehicle air pollution Tunnelsand Underpasse s Waller et al. (1961)measured average CO concentrationsin London'sBlackwell and RotherhitheTunnel. The averageCO concentrationsduring the morning and eveningrush hours were slightly above100 ppm. PeakCO concentrationsof 500 ppm, 450 ppm, and 340 ppm wererecorded on daysfor which fans in the tunnel were shut off. Coviauxet al. (1984)measured CO concentrationsin a tunnelin Paris,France. They found averageCO concentrationsof 30 ppm in the tunnelitself and6 ppm in 'technical a room' that supportedoperation of the tunnel. However,smokers werepresent in the room. Lonnemanet al. (1986)reported that measurementsof non-metlaneorganic carbontaken in 1982in New York's Lincoln Tunnelwere one-fourth the levels found in a L97Ostudy of the samesite. They attributedthis reductionto the greaterprevalence of catalyticconverters in the motor vehiclepopulation, because tunnelventilation rates for eachyear had not changed. Wright et al. (1975)reported that averageCO concentrationsin six poorly ventilatedunderpasses in Toronto,Canada ranged from 17.5 - 100+ ppm. Parking Garagesand SemiceStations Studiesofparking garageshave been done in severalcountries prior to the introductionof emissioncontrols on c:us. Trompeoet al. (1964)measured CO levelsin 12 undergroundgarages in Rome,Italy. The CO levelsfor 132 observationsaveraged 98 ppm andranged from 10 - 300 ppm. Chovin(L967) recordedaverage levels of 150ppm between7:30 and 8:00 a.m. in a police car garagein Paris,France. Wright et al. (1975)reported that averageCO concentrationsin well-ventilatedunderground garages in Torontoranged from 7.4 - 34.7 ppm. Severalstudies have examined the diffi,rsionpotential of air pollutantsfrom parkinggarages into adjacentbuildings. Yocum et d. (1971)monitored inorganic Pb particulatesand CO concentrationsin buildingsin Hartford, Connecticut. Althoughone building was built over a parkingg:uage, its ventilationsystem, which wasoperated with a slightpositive pressure, was effectivein preventingthe penetrationof inorganicPb particulatesfrom autoexhaust. Jabaraet al. (1980)collected 8-hour CO exposuresof65 employees,including smokersand nonsmokers,of the Denver,Colorado Police Department who workedclose to heavytraffic for extendedtime periods. A groupof 33 office 94 Human exposureto motor vehicle air pollutants employeesserved as controlsfor comparison.Table 5 summarizesthe resultsfor 8-hourCO concentrationsfor eachtype of employee.The highermedian concentrationfor office nonsmokerswas attributedto five high readingsamong employeeswho workedin offrcesabove a parking garagein the police station. Jabaraet al. concludedthat CO leakedupstairs from the garageon very cold morningswhen garage doors were closed and vehicles were being warmed up beforeleaving. Table5. Typical 8-HourCO Exposures(ppm) in Denver,Colorado in t978 - t979. Type of Nonsmokers Smokers Exposure Median Range Median Range Offrce 7.5 4.2- 22.1 7.1 4.r - 9.6 '1.8 Trafftc 20.4 - +4.3 22.1 8.0- ss.3 Ott andFlachsbart (1982) reported that ten enclosedparking garages in several Californiacities had a meannet CO concentration(after subtractingthe ambient concentrationsat the nearestfixed-site monitors) of 21.7 + l2'5 ppm. Seven buildingsattached to enclosedparking garages had a meannet CO concentration of 6.1 + 2.9 ppm. For a givendate and microenvironment, CO concentrations werefound to be relativelystable over time, which suggestedthat brief visits to eachmicroenvironment could enable generalizations to longertime periods. Flachsbartand Ott (1986)observed the diffusionof CO from an underground parkinggarage into the upperfloors of a l5-story office buildingin Palo Alto, California. A surveyof the entirebuilding showed that averageCO concentrationsin the garagewere 40.6 ppm andranged from 10.2- 18.5ppm for the first 11 floors aboveground level. High CO levelsin the buildingwere attributedto two factors:(1) fansventilating the garagewere shut down to reduce electricitybills; and (2) the doorsconnecting the stairwellto the garagewere left open. AverageCO levelson the top four floors rangedfrom 2.0 - 4.0 ppm, becausethey were servedby a separateventilaticn system. Oncethese problems weremitigated, average CO levelsin the garagedropped from 40.6 ppm to 7.9 ppm andin the buildinghad fallen to just 0.7 - 1.5ppm. Flachsbartand Brown (1989)systematically surveyed 25 businessoutlets for employeeexposure to CO on the groundlevel of the Ala MoanaShopping Center 95 Motor vehicle air pollution in Honolulu,Hawaii. The shoppingcenter is attachedto a multilevel,semi- enclosedparking structure. At groundlevel the structurehas a two-lanedriveway fronting shops,most of which leavedoors open during business hours. The averageco concentrationsfor 30 visits to all shopsover the five-monthsurvey rangedfrom 2.8 - 23.1 ppm. co readingsat the nearestfixed-site monitor were usuallybelow 1 ppm. A similar studyof the sameshopping center by Bachand Lennon(1972) found averageCO levelsranging from 12 - 37 ppm in parking areas. Flachsbartand Brown attributedtheir findingsof lower averageco levels primarily to stricteremission controls as appliedto new motor vehiclesduring the 11 yearsbetween the two studies. Servicestations were includedas microenvironmentsin two studies. Amemdale andHanes (1984) measured CO concentrationsin 13 automobileservice stations andtwo dealershipsin the New Englandarea. Resultsvaried by season,with co concentrationsranging from2.2 -2l.6ppm in warmweather and 16.2 - 110.g ppm during cold weather. They cited reducedventilation for higher concentrationsduring winter. wilson et al. (1991)randomly sampled 100 self-servicefilling stationsand took conveniencesamples at l0 parkinggarages and 10 officesnear the garages,in the Los Angeles,orange, Riversidl and San Bernardinocounties of southerncalifornia. They took five-minutesamples of 13 motor vehicleair pollutantsin eachmicroenvironment and in the ambient environment.Table 6 summarizesresults for just the motor vehicleair pollutants. Table6. MedianS-Minute Concentrations (ppb) of Motor VehicleAir Pollutantsin SouthernCalifornia in 1990. Motor Vehicle Service Parking Office Air Pollutant Station Garage Building Ambient Benzene 9 2l 5 4 Carbonmonoxide 4300 l 1000 4000 2000 Ethylenedichloride 0.1 0.1 0.1 0.1 Formaldehyde 4 34 36 20 m-/p-xylenes 13 43 9 9 Toluene 36 49 26 29 Curb-sidesin CommercialAreas In threeu.s. cities, colucci andBegeman (1969) found that outdoormean co concentrationswere usually the highest,but variedthe mostin commercialareas - (3.5 l0 ppm), were intermediatenear freeways (6 - 8 ppm), and werelowest in 96 Human exposureto motor vehicle air pollutants residentialareas (2.5 - 5.5 ppm). Similarly, Godin,Wright and Shephard(1972) observedthat CO concentrationswere highest in downtownToronto, intermediate at a suburbanhome, and lowest at a semi-ruralfarm house. Ott andEliassen (1973) collected CO samplesin downtownSan Jose, California and in surroundingresidential and industriallocations. They reportedaverage CO levelsranging from 5.2 - L4.2ppm for sidewalksalong congested downtown streets,with correspondingaverages at fixed-sitemonitors ranging ttom2.4 - 6.2 ppm. Wright et al. (1975)measured 4 - 6 minuteaverage CO exposuresof pedestrians and street-workersduring summerand fall 1973in Toronto, Canada. They focusedon sidewalksthat hadbeen closed to traffic to becomea pedestrianmall. Beforethe streetwas closed,the averageCO concentrationsat two crossstreets were9.4 t 4.0 ppm and7.9 * 1.9 ppm. After the streetwas closed, the averagesdropped to 3.7 + 0.5 ppm and4.0 t 1.0 ppm, respectively,roughly equivalentto the urbanbackground level. Wilson and Schweiss(1978a) measured CO concentrationsat 40 outdoorsites and four sidewalksin Boise,Idatro. Pedqstrianexposures ranged from 2.9 - 14.0ppm fot 2 - 4 hour averages.The highest8-hour CO averagewu l7 .2 ppm. In downtownSeattle, Wilson andSchweiss (1978b) measured CO concentrationsat 36 outdoorsites (including small parks and isolatedareas) and two sidewalks. The 4-houraverage CO levelsalong sidewalks ranged from 1.1 - 11.9ppm' Bellin andSpengler (1980) measured the CO exposuresof baggagehandlers at Boston'sLogan International Airport. They intermittentlymonitored both the upper (open)and lower (semi-enclosed)levels ofthe entrancearea ofone terminal. Basedupon l5-minuteaverages, the indoor (ticketcounter) concentrationswere significantlylower thanthe outdoor(curb-side) concentrations.The 95 percentconfidence interval for all indoorlocations (5.7 - 6.8 ppm) waslower thanthe intervalfor all outdoorlocations (9.7 - 12.5 ppm). The l-hour maximumconcentrations were 15 ppm (indoors)and 23 ppm (outdoors),both occurringon the sameday. The Air Qudrry and NoiseDivision of the NationalEnvironment Board of Thailand(1989) has measured curb-side concentrations of severalmotor vehicle air pollutantsin Bangkoksince 1984. Between1985 and 1987,daily levelsof particulatematter slightly exceededthe ambientstandard of 330 pglm3 and at one locationwere two to threetimes the standard.Average daily Pb concentrationsat 18 sitesmonitored between 1985 and 1987ranged from 0.6 - 3.5 pglm3, which wasbelow the ambientstandard of 10 pglm3. MeanCO valuesfor 17 sites monitoredbetween 1985 and 1988ranged from 3 - 24 mgtmi for l-hour 97 Motor vehicle air pollution averagingtimes and from 2 - 26 mg/m3for 8-houraveraging times. The l-hour and 8-hourco standardsare 50 and20 mglm3,respectively. No2 ando3 levels werereported to be low. PerpendicularDistance from Roads Besnerand Atkins (1970)investigated the relationshipbetween motor vehicleair pollutantsand perpendicular distance to the axis of an urbanexpressway in Austin, Texas. concentrationsof co andPb weremqxured at two sites,one 4.8 meters andthe other 29 metersfrom the road. At both sites,they found a strongpositive associationbetween Co andPb concentrations.They alsoreported a declineof co concentrationswith greaterdistance from the road, verifying a similar finding by Ramsey(1966). At the site nearestthe road, co concentrationsranged from 3.4 - 6.0 ppm, whileat the moredistant site they ranged from 2.4 - 3.9 ppm. Indoor-O ut do or Relat ionship s In the Hartford, connecticutstudy, yocum, clink andcote (1971)found that co concentrationsin enclosedsettings are similarto outdoorconcentrations, but tend to lag behindthe peakconcentrations observed outdoors. Godin,wright and Shephard(1972) reported similar findingsfor downtownoffices in Toronto, canada. They foundthat indoorco concentrationstended to matchoutdoor levels,but with a lag of I - 2 hours. The GeneralElectric company (1972) studied co concentrationsin two high-rise buildingsin New York city, one constructedover a highway. They found that indoorCO concentrationsnormally were lower than outdoorconcentrations at all heightsabove ttre roadwaywhen outdoor concentrations were high. conversely, whenoutdoor concentrations were low, indoor concentrationswere not as low. Hence,in the absenceof indoorco sources,indoor concentrationstended to follow outdoorlevels with somedegree of time lag andwith a tendencynot to reacheither the extremehigh or low valuesthat were foundoutdoors. The study alsoreported that at heightsgreater than 30 metersabove the roadway,CO concentrationswere larger indoorsthan outdoors. This resultwas attributedto the trappingof CO within the building. Estimatesof PeopleExposed This sectionprovides crude estimates of the numberof peopleexposed to motor vehicleair pollutantsin developedand developing countries on a daily basis. Very few studieshave actually attempted to estimatethe numberof people exposedto motor vehicleair pollutantsin differentmicroenvironments, such as insidevehicles and alongroadsides. Hence, these estimates are based on a 98 Human exposureto motor vehicle air pollutants numberof critical assumptionsmade necessary by a lack of literatureon the subject. AppendixA describesthe methodologyunderlying these estimates. A basicassumption applicable to all microenvironmentsis that humanexposure to motor vehicleair pollutionis largelyan urbanphenomenon. For example, Romieuet al. (1991)reported that mobilesources in Santiago,Chile are responsiblefor 83 percentof total NOr emissions,78 percentof hydrocarbons, and98 percentof CO emissions.Nearly everystudy reviewed previously focused on highwaysand roadside settings in urbanas opposedto rural settings. In comparisonto rural areas,cities have greater traffrc congestion,which lowers averagetravel speedsthereby increasing some types of emissions,and their businessdistricts have street canyons which increaseconcentrations. Although motor vehiclespervade rural areasalso, motor vehicleair pollutionis a much greaterproblem in cities. Hence,a country'slevel of urbanizationis one indicator of the numberof peopleexposed to motor vehicleair pollution. A secondbasic assumption is that the numberof peopleexposed to air pollutants from motor vehiclesdepends upon the extentto which a countryis motorized. Zahavi(L976) defined motorization at the countrylevel as the numberof carsper 100population or the numberof carsper household.Countries with higherlevels of motorizationare consideredmore susceptibleto havinggreater numbers of pmple exposedto motor vehicleair pollutants. A countervailingfactor to the extentof motorizationin a particularcountry is the level of emissioncontrols applicable to motor vehiclesin that country. Renner (1989)briefly summarizedthe historyof emissioncontrols in differentcountries. In the United States,emission controls on motor vehicleswere first implemented in the 1960sand emissionlimits weregradually tightened throughout the 1970s. Japan'semission standards, which are comparableto U.S. limits, were implementedin 1975and 1978. More recently,Australia, Canada and South Koreaadopted emission standards equivalent to thosein the U.S. The European EconomicCommunity @EC) has adopted separate standards for large,medium andsmall vehicles. Smallcars, which captureabout 60 percentof the European market,have the mostlenient emission standards. Brazil expectsto matchcurrent U.S. standardsby 1997. Many other countries,such as Argentina,India and Mexico, havevirtually no controlson motorvehicle emissions. A third basicassumption is that urbanizationand motorization vary by countryand that countriescan be groupedaccording to the extentof their economic development.Based on standarddefinitions used by the World Bank (1990),four economicgroups are definedhere based on per capitagross national product (GNP). Thesegroups are as follows: 99 Motor vehicleair pollution Country Per CapitaGNP EconomicCrouo (1988U.S. Dollars) Low income $100- 490 Lower-middleincome $570- 2,160 Upper-middleincome $2,290- 5,420 High income $6,010- 27,500 Table7 summarizesboth the world's humanand automobilepopulations by these four economicgroups, which include159 countries representing 99.8 percentof the world'stotal population of 5.313billion people in 1990. (Ihis world populationtotal includesabout 20.5 million peopleliving in Taiwanin 1990,but excludedfrom TableA.4 of the United Nationsreport titled World Urbanization Prospects1990, which wasthe basisfor the estimateof humanpopulation.) In 1990,while high-incomecountries had only 22.7 percentof the globe's population,they had 37 percentof the world's urbanpopulation of 2.4 billion peopleand an astounding85.6 percentof the world's automobilefleet of 405 million vehicles. Middle-incomecountries, including both lower-middleand upper-middlecategories, had 20.4 percentofthe globalpopulation, but 26.3 percentof the world's urbanpopulation and 12.7percent of all automobiles.In contrast,the low-incomecountries had 56.9 percentof globalpopulation, but only 36.7 percentof urbanpopulation and only 1.7 percentof the world's automobile fleet. The mostfrequent means of travel in low-incomecountries is by foot and paratransit. The latter includespedal or motorizd rickshaw, convertedvans and 100 Human exposure to motor vehicle air pollutants o o O :.at € \O alt\O - 6 j \n -l O c) t \O Nl N C.l C 6 Nl C.l ila ooi = xl cl (n ol \o \o o T \o ol 6 - e.l \t \ol \t o \o h -l \o llo o-idl-: de.iqvicjld Jci-;Jli -i.rFe'ild llc; *E€tr| doo '€ x9 ilE fits: qaqRs.R i $.ls. qH s.qaeJa €5 ( siF.El s€81€ Eq€eq6 qnEqq qqqqE ile *;dlg sidct=dl$ -':-:r6il\d i:"ddli EESEI ilg bo 6.) cr 8l 6 trtl c-i-ralo\ 6to66lr €moolo\ \o!ao@l 6 ll@ d O al t\o-lc\ oott\o€l 6l EhhNlO\ ttl..\OlC.l llN f i'al c|o\-l o ortrrol F- \oo\rhl 6 oFraoll o\ llo\ -\ -h-l \O -5-ixl FO\Cll 6 t FO@O\l FhFFI r 116 pxl -v.r lF \ora \o 16 m('|cltl rt otFrorl co llo\ i{ EF l€ c.l tr r- (?r6e.r a-l-' l@ ilq d llc.l o o 4 El (\16r{'l r+ 6o\\ototar ti6Fl 6 For@l \o llo c{€ oO; Al d\Odl 6 C-,-c)--l Al N€c)Ol d FmC.l 6l \O llo rc{ .d dlg ci 6 |I a dl o-o\to @Fhoht @ €h6rfl\o o\i6\al@ llcl o : -l.J q - c)l : \a F t N +l O c.l o\ c) F-l O d i u') \ol t [r 5i 6, E Exl Fl€.6lvl qvrelarJq o-qqo\J€- o-.!qallq [c: $nl3 3$-H."ls€$n8lF $3X14 SR EE3 il3 d6i q? tsi PX k{x !?l :6oll \O \ 6-OFl \o r^sl\aFl o\ GIO\tcrl @ llo\ -.El oH ,!q. N ,h ,r ic{ ,m t*> il! { vv EEI = x$ '!'i + (l Sc') .s .s F- EE JTIE (l(Jo. a FJ E5 E 5 E 5 ' 5 .\{$s &l tiig tI e di e lri -g 6 E ;l Ef H : , sse::- El €E F =* :q Eo €.o H E = E E E NE; B :l f E !* \fN tr :s <<€ o ots F- (.) gFFa;fiF= F fl:,iiE,islfiiul*lgi*;fi:€r>; 101 Motor vehicle air pollution pickups,converted jeeps, small minibuses, shared taxis, motorcyclesand mopeds (Armstrong-Wright,1986; White, 1990). Bleviss(1990) reported that sharesof the world's automobilefleet are shifting amongdifferent countries and regions. The U.S. shareof the world's automobile populationhasfallen ftom77 percentin 1930to 35 percentin 1986. By the year 2000, Europewill havemore automobileson the road thanthe U.S. (OECD, 1983). Althoughdeveloping countries cunently have small shares of the world's automobilefleet, countriesin Asia and Latin Americaare expectedto doubleor triple their automobilepopulations by the endof this century. Numbers of In-Vehicle Exposures Table8 summarizesthe estimatesof dailyvehicular trips in urbanareas by econornicgroup andregion in 1990,as further brokendown by travel mode. This tableshows the grossdisparity in both the absolutenumbers and the percentages ofvehicular trips for developedand developing countries, particularly between oppositeends of the incomespectrum. This disparityin urbanvehicular trips is evenmore pronouncedwhen one looks at trips by automobileversus trips by public andpara-transit. The high incomecountries, which claim only 37 percentof the world's urban populationof 2.4 billion people,account for a disproportionatelyhigh shareof the world's daily vehiculartrips in urbanareas. Of the 3.4 billion vehiculartrips takenevery day in cities,over half takeplace in high-incomecountries and almost 72 percentof theseare by automobile.The lower-middleand upper-middle incomecountries combined, which represent 26.3 percentof the world's urban population,account for only 21.1 percentof all vehiculartrips and 14.1percent of the automobiletrips. In contrast,the low-incomecountries, which represent36.7 percentof the world's urbanpopulation, account for only 27.2 percentof the world's vehiculartrips andjust over 14 percentof its automobiletrips in urban are:N. Numbers of RoadsideExposures Exposurealong roadsides is a functionof the streetscapeand how peopleuse streetsto travel anddo business.In urbanareas, the greatestpotential for exposureoften occursin businessand commercialdistricts. However,many developedcountries have shopping centers that are designedto separate pedestriansand motor vehicles. In developingcountries, sidewalks are often narrowor non-existentin commercialdistricts. Proudloveand Turner (1990) describetlpical streetconditions in manyThird World Cities. Streetvendors and hawkersin developingcountries take up so muchsidewalk space that pedestrians ro2 Human exposure to motor vehicle air pollutants o= ?€.:t or @rn \ot\lc)td-t @ rn r, o vl a.l o N t+ et ir c{.J q= @l \OO\Ol \O r+(\OolOl 6 ! -t cl ql a -1nqqq ll<) +Rols ci6dedl= i i *:t\o o\ t \o cl o llei f;fFIEl ls llo KE!E EI d Sddl 6-e t+ C- \a \Ol al 6 d d alll- Io $EEF€l q\q{ tEqqqlE q9nYtq q q q !19 Iq Fr; dr: = >. !.: Al C\ < €l € ...1 -. = a ! >t - o r-.t @ r @ s \o 6le 6 \a F Flal o\ € 6 Nl e{ ilo qqq9el\ rlq\ln ! g: ql\ ilc ;"{i al :::l:N 'c{ - f) O @ Ol \a H - H *l r, F- O\ + Ol - llc) ! $'>i tl In ll9 F FES 3 tr,v 'Elc{ lo r FI F #5€E3R:RI; EfrEHiI€ HNSH$ HSE$IRflN 5 Fi .:r Jlr -1" ,? qi j$ -1,{i 223}-"5 1 : e3Il A "iltr13 €r R l3 {6o\bt@e a]j **i-l:a ll.i ll: C) .FAEcE Fgg,E$ >.' 'o El tr'tr'ih il Ed E d E (5 ; ci .91 tii 9 ur o rii 9 di _g 6 ;l €: E * : H € : € ; cl !a i € i 5 ! ; = F E 3| ;; : T In -E = : = r.e :Ix :E = : E€ E : E E: E€ 3 00 o slsgl; tsr*:* isE*: !:pi* f F filiE?5 itxnis $tx,i5 E"x;tE I 103 Motor vehicle air pollution are often forcedto walk in the streetin a zoneintermediate between the sidewalk andmoving motor vehicles. Table9 summarizesthe resultsof estimatesof roadsidepopulation by economic group andregion. The tableshows that citiesin low-incomecountries have an estimated62 to 103million peoplewho spenda considerableamount of their working day in roadsidesettings. Their roadsidepopulation is roughly 1.7 times as large as that found in all middle-incomecountries and 2.3 to 2.7 timesas large as ttratfound in high-incomecountries. For low- andhigh-income countries, a comparisonof Tables7 and9 showsthat their respectivepercentages of the total roadsidepopulations roughly correspond to their respectivepercentages of the world's total population. For lower-middleand upper-middle income countries, the samecomparison shows that their respectivepercentages of the total roadside populationsroughly correspond to their respectivepercentages of the world's total urbanpopulation. Conclusion Severalconclusions can be drawnfrom studiesof humanexposure to air pollutants from motor vehicles. First, numerousstudies have shown that concentrationsof someair pollutantsinside motor vehiclesand along,roadsidesare typicallyhigher thanthose levels recorded simultaneously at fixed-sitemonitors. Second, exposurestend to be higherinside automobiles than in transitvehicles used by bus andrail systems.Third, priority lanesused to afford speedadvantages to carpools andbuses can reduce air pollutantexposures of their passengers.Fourth, in the absenceof indoorsources, concentrations in enclosedsettings are similarto outdoorconcentrations, but tendto lag behindthe peakconcentrations observed out{gors. But indoor concentrationstend not to reacheither the extremehigh or low valuesthat are found outdoors. The exceptionsare certaincommercial buildingsthat are attachedto activelyused parking garages. When ventilation systemsin thesebuildings are not functioningor operatingproperly, motor vehicle emissionsfrom garagescan infiltrate buildings and exposeoccupants to concentrationshigher than ambient levels. Fifth, concentrationsof motor vehicle air pollutantsdecline with greaterdistance from the road. This suggeststhat passengersin vehiclesare at mostrisk to air pollutantsfrom motor vehicles, followedby pedestriansand street merchants along roadsides, and then the general urbanpopulation. A country'slevel of economicdevelopment also plays a significantrole in human exposureto motor vehicleair pollutants. Developednations have larger urban and automobilepopulations than developing countries, and consequently greater mobility andlarger proportions of trip makerswho useautomobiles rather than public transit. Thus, the potentialfor humanexposure to air pollutantsfrom 104 Human exposure to motor vehicle air pollutants e"E,eii cr c'rd'! -re e:t\ gE.g '$ olS : E; x:l: :: - -i"?:.ll: e'il6 oi: FI v;cilF llg € El rd il=ll8 Ei- x€'€l b d **l BU ; ::: gi €€ El $;l; :3: I3lff'' il3 i $::13rr=il! AH=E{*E r3l St:g.Eg Sfrll! ;3=SslF 3Ss!15 sr$sF iln o\ '.E5egl o\ 3$lg ;I-k Ir 3:;:l$ a3*1$ 'eeF ll$ bo u;3Fg3F1B s*-a1t iiBx|: ip*$lR :J il3 O tr Q rrl q 9Al er!q*l O\ olQ!!@91 F @q\\aO\l r 6\OC\@trt il- >l €Egl qqqE 8.{3;-ela c^8.€-sJqs^qeslq llq ';u5EOl $gcioi l:lFi Rfii E'lE =:s=lR g3E*l$ n*llg 5 o E55EE€€,tr Br ?d E 3 E 5 u E q H !r t s ? i * € il sl g E :. EE r E:. rrl A gE 5 € EE5 : E ,* Ej o\ c) EIEsI!xs;*;* Es.Is;fEs;a 3 Eli5x5EEIESE EqiEE f,.i;Ee ! L1 rIlJ J 5 E 6 105 Motor vehicle air pollution motor vehiclesis higherin developedcountries, because these risk factorsexist. However,there is preliminaryevidence from North Americancities that, despite growth in automobilesand traffic volumesduring the last 20 years,human exposureto somemotor vehicleair pollutantshas declined due to tighter emission controlson cars. Humanexposure to air pollutansfrom motorvehicles in largecities of developing countries,such as Mexico City, presentlyappears to be evenhigher than exposuresobserved in largeU.S. citiesduring the 1960s,prior to the adventof motor vehicleemission controls in the U.S. Althoughdeveloping countries typically havelower levelsof motorization(i.e., fewer automobilesper 1000 population),each vehicle is likely to emit more air pollutantsper mile thanthe vehiclesin developednations due to a lack of or lessstringent emission controls, and/orpoor qualityfuels. Furthermore,these levels of motorizationare growing rapidly, especiallyin Asia andLatin America. Finally, large citiesin developing countrieshave much greaterpercentages of their informal labor forces who are streetvendors and hawkers than do citiesof developedcountries. Thus, actual levelsof humanexposure to motor vehicleair pollutantsmay be higherin developingcountries. 106 Humen exposureto motor vehicle air pollutants REFERENCES Air Quality andNoise Division. Air and noisepollution in Thailand1989. Offrce of the NationalEnvironment Board, Bangkok, Thailand, (1989). Akland, G. et al. Measuringhuman exposure to carbonmonoxide in Washington, D.C., and Denver,Colorado, during the winter of 1982- 83. Envirowrcnal Scienceand Technology,19: 91 1-918 (1985). Amemdale,A. & Hanes,N. Characterizationof indoorcarbon monoxide levels producedby the automobile.Indoor Air, Volume4, ChemicalCharacterization andPersonal Exposure, B. Berglund,T. Lindrall & J. Sundell,eds., NTIS PB85-1M214.Swedish Council for BuildingResearch, Stockholm, Sweden. pp. 97-r02(1984). Armstrong-Wright,A. Urbantansit systems:guidelines for exaniningoptions. World Bank TechnicalPaper Number 52, Washington,D.C. (1986). Bach,W. & Lennon,K. 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Archivesof EnvirownentalHealth, 35: 198-204(1980). 109 Motor vehicleair pollution Johnson,T. A studyof personalexposure to carbonmonoxide in Denver, C.olorado.Paper No. 84-121.3presented atthe'77th Annual Meeting of the Air PollutionControl Association, San Francisco, California, (1984). Lonneman,W. et al. Non-methaneorganic composition in the Lincoln Tunnel. EnvirorunentalScience and Technology, 20:'l 90:796 (1986). Luria, M. et al. Five yearair qualitytrends in Jerusalem,lsrael. Atmospheric Envirownent,19 : 7 15-726(1985). Myronuk, D. Augmentedingestion of carbonmonoxide and sulfur oxidesby occupantsof vehicleswhile idling in drive-upfacility lines. Water,Air, and SoiI Pollution, 7 : 203-21.3(1977). Organizationfor EconomicCo-operation and Development. Cities and transport. OECD,Paris, France, (1988). OrganDationfor EconomicCo-operation and Development. Long term outlookfor the world automobileindustry. OECD, Paris,France, (1983). Ott, W. Modelsof humanexposure to air pollution. SIMS TechnicalReport No. 32, Departmentof Statistics,Stanford University, Stanford, California, (1980). Ott, W. & Eliassen,R. A surveytechnique for determiningthe representativeness of urbanair monitoringstations with respectto carbonmonoxide. Journalof the Air Pollution ControlAssociation,23: 685-690 (1973). Ott, W. & Flachsbart,P. Measurementof carbonmonoxide concentrations in indoor andoutdoor locations using personal exposure monitors. Environnent InterrutionaL,8: 295-304(1 982). Ott, W. et al. Carbonmonoxi.de exposures inside an automobiletravelling on an urbanarterial highway. PaperNo. 91-138.1presented at the 84thAnnual Meetingof the Air andWaste Management Association, Vancouver, British Colombia,(1991a). Ott, W. et al. Carbonmonoxide exposures inside an automobiletraveling on an urbananerial highway. SIMS TechnicalReport No. 150,Department of Statistics,Stanford University, Stanford, California. In press(1991b). Ott, W. et al. Trendsof in-vehicle CO exposureson a California arterial highway over onedecade. Paperpresented at the conferenceof the InternationalSociety of ExposureAnalysis, Atlanta,Georgia, (1991c). 110 Hunranexposure to motor vehicle air pollutants Petersen,G. & Sabersky,R. Measurementof pollutantsinside an automobile. Journal of the Air Pollution ControlAssociation,25:. fi28-1032 (1975). Petersen,W. & Allen, R. Carbonmonoxide exposures to Los Angelesarea commuters.Journal of the Air Pollution hntrol Association,32:.826-833 (1982). Proudlove,A. & Turner, A. StreetManagement. Transport Planningfor Third WorldCities, H. Dimitriou,ed., Routledge,London, England. pp. 348-378 (lee0). Ramsey,J. Concentrationsof carbonmonoxide at traffic intersectionsin Dayton, Ohio. Archivesof EnvironmentalHealth, 13: 4446 (1966). Renner,M. Rethinkingtransportation. State of the World 1989, W.W. Norton andCompany, New York, New York, (1989). Romieu,I. et al. Urban air pollutionin Latin Americaand the Caribbean. 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SouthCoast Air Quality ManagementDistrict, El Monte, California,(1991). Wilson, C. & Schweiss,I. Carbonmonoxidestudy - Boise,Idatn, November 2j-December22, 1977,Pan 2. EPA-910/9-78455b.U.S. Environmental ProtectionAgency, Region X, Seattle,Washington, (1978a). Wilson, C. & Schweiss,J. Carbonmonoxide study - Seattle,Washington, October6-November 2, 1977,Pan 2. EPA-910/9-78-0546.U.S. Environmental ProtectionAgency, Region X, Seattle,Washington, (1978b). World Ba*. World DevelopmentRepon LW. Oxford University Press,Oxford, England,(1990). World Urbanizaion Propects 1990. Depa*mentof InternationalEconomic and SocialAffairs, UnitedNations, New York, New York, (1991). Wright, G. et al. Carbonmonoxide in the urbanatmosphere: hazards to the pedestrianand street-worker. Archivesof EnvirorunentalHealth, 30: 123-129 (1e75). Wright, 1., efi' The UniversalAlmanac 1992. Andrewsand McMeel. New york. pp. 345-416(1991). Lt2 Human exposure 0o motor vehicle air pollutants Yocum,J. et al. Indoor/outdoorair qualityrelationships. Journa| of the Air Pollwion Contol A sso c iat ion, 2 | : 25L -259 ( 197 I ). Zahavi, Y . Travel characteristicsin cities of developingand developedcountrfus. World Bank Staff Working PaperNo. 230, Washington,D.C., (1976). Ziskind, R. et al. Pilot field study:carbon monoxide exposure monitoring in the generalpopulation. EnvironmentInternational, 8: 283'293(1 982). 113 Chapter4 REVTEWOF MOTOR VEHICLE ENIISSIONCONTROL MEASI,JRES AND THEIR EFFECTIVENESS MichaelP. Walsh" Introduction: elements of an overall pollution control strategy Generally,the goal of a motorvehicle pollution control program is to reduce emissionsfrom motor vehiclesin-use to the degreenecessary to achievehealthy ambientair qualityfor mobilesource related pollutants in all areasof a city or countryas rapidly as possibleor to the practicallimits of technological,economic and socialfeasibility. In orderto achievethese general goals, emission standards to achievethe desiredreductions need to be set andprograms implemented to enforcecompliance with thesestandards and to controlvehicle usage where needed.These emission reduction goals are to be achievedin a mannerwhich is equitablewith respectto the populationgroups affected and, wheredirect trade- offs betweenalternative approaches exist, in the leastcostly manner. MichaelP. Walsh,Consultant,Arlington, Virginia, United Statesof America 115 Motor vehicle air pollution Strategy Analysis Two waysof controllingmotor vehicleemissions are to controlemissions per vehiclemile traveled(VMT), andto controlVMT. Thesemethods can be used together. Controlling Emissionsper Mile Driven Emissions/VMTmay be reducedby controlling(1) vehicleperformance and/or (2) fuel composition(e.g., lead,sulfur, volatility, oxygencontent). VehiclePerformance Vehicleperformance may be improvedby controllingvehicle hardware and by ensuringthat vehiclesin-use are properly maintained. vehicle hardwaremay be controlledby requiringvehicles to be designedand built to meetemission standards when new andduring their usefullife (arbitrarily definedas 5 years;50,000 miles prior to 1990in the US althoughit is recognized that a vehicle'stotal lifetime is muchlonger if properlyused and maintained)and to be modifiedif they do not. Sincethe emissionstandards of concernrepresent substantial reductions in emissionsfrom uncontrolledvehicle levels, it is necessarythat manufacturers consciouslydesign their vehiclesfor emissionscontrol. vehicle designmay be evaluatedby testingprototype vehicles. If individuallyconstructed prototype vehiclesare not capableof meetingemission standards, it is generallyaccepted that massproduced vehicles of the samedesign probably are not either. Conversely,if manufacturersare ableto build prototypeswhich demonstratethat their designsare capableof meetingstandards, the pioUaUititythat their production vehicleswill alsomeet standards may be increased. VehicleBuild - New Giventhat the manufacturerhas "certitied"his intendeddesign, production vehiclesmay not meetstandards, even when new, eitler becausethey are not constructedin all materialrespects, the sameway as the prototype(i.e., they are misbuilt),or the manufacturerhas failed to translatethe designeffectively into massproduction. The first situationis legallyequivalent to introducticjninto commerceof an uncertifieddesign and may be guardedagainst by inspectionsand civil penalties. 116 Control measuresand their effectiveness The secondsituation may resultfrom "prototype-to-productionslippage" and/or "productionvariability", dependingon the circumstances.In that case,Ole vehiclesmay not conformto the standards,but productionvehicle testing is the only way their nonconformancemay be detected.Therefore, testing of production vehiclesis necessaryin orderto be certain0rat production vehicles actually meet standards. VehicleBuild - UsefulLife Vehiclesmay meetstandards when new but may fail to meetstandards during their usefullife, eventhough properly maintained, due to excessivedeterioration in-use. Suchdeterioration may occurbecause the manufacturerfailed to translate effectivelythe designinto massproduction, or becausethe certifieddesign is inadequatedue to the inability of the acceleratedcertification testing to accurately simulatein-use standards. In suchcases, it is desirablethat the manufacturerbe requiredto fix the vehicleat his own expensefor two reasons;one, !o reduce emissionsfrom the vehicle,and two, to deterthe manufacturerfrom building such vehiclesin the future. Mechanismsfor identifyingexcessively polluting vehicles in-use include in-use testing,defect reporting by manufacturersand by vehicleowners, state inspection programs,and assembly-linetesting. Mechanismsfor requiringmanufacturers to fix suchvehicles are providedby recall andwarranty progranu. ProperMaintenance Vehiclesmay havebeen designed and built to meetstandards but they will not do so unlessproperly maintained. To the extentthat motorvehicles can be designed to eliminateor minimizenecessiuy maintenance, the magnitudeof this vital taskof ensuringproper maintenance can be reduced.A meansfor achievingreduced maintenancerequirements might be to force technologyby graduallyrequiring manufacturersto reducemaintenance performed during certificationtesting and to similady reducethe pre-requisitemaintenance for warrantypurposes. However, the inability of the certificationprocess to assessthe needfor time dependent(as opposedto mileage-dependenQmaintenance suggests that warranty requirements would be a principleenforcement tool. The fundamentalrequirements for achievingproper maintenance of vehiclesin-use would seemto be providing(i) the incentivefor car ownersto obtainproper maintenance,and (ii) the ability andincentive of the marketplaceto provideproper maintenance. 1t7 Motor vehicle air pollution Owner Incentive Requiringmaintenance tlrrough a mandatoryI/M (inspectionand maintenance) programwould be the mosteffective "incentive" for car owners. The successof an I/M program,either in termsof maximizingemission reduction benefits or in termsof obtainingpublic acceptance,depends upon rqNsuring the public that manufacturersare doingtheir part, i.e., tlat the vehiclesare designedand built to meetstandards if properlymaintained, and that manufacturerswill bearLhe eost if they do not meetstandards. A significantaspect of an I/M programis the inspectiontest used to identifo vehiclesin needof maintenance.A shortinexpensive test which correlateswith the full test is highly desirable. Sucha testwould not only makethe I/M program more costeffective in termsof direct emissionreductions capability, it would also makethe inspectionsan extremelyvaluable surveillance tool for usein conjunction with assembly-linetesting, recall, andwarranty progr:rms, and it would makeI/lvI more palatableby activatingthe performancewarranty. MarketplaceAbility The ability of the markeplaceto provideproper maintenance is first dependenton knowingwhat propermaintenance is, andmanufacturers are requiredto speciff such "reasonableand necessary"maintenance in owner'smanuals. Review of thoseinstructions by an agencysuch as the UnitedStates Environmental Protection Agency(USEPA), to ensurereflection of at leaststate of the art technologyin reducedmaintenance requirements can be important. Manufacturersmay alsobe requiredto designtlreir vehiclesand maintenancerequirements to avoid "foreseeable"instances of improperor mis-adjustment.where particularfuels are requiredas in the caseof unleadedgasoline for catalystequipped vehicles, that fuel mustbe madeavailable. Further,msnures mustalso be taken(such as labels in the filler inlet areaand on the dashboard;fuel filler inlet restrictorsdesigned to accommodateonly the slightly narrowerfuel nozzlethat shouldbe usedfor unleadedfuel) to be surethat vehicleowners and drivers are fully awareof the needfor unleadedfuel in their vehicles. Also, someconsideration should be given to pricing policiesfor unleadedand leaded fuels so that vehicleowners and drivers do not havean economicincentive to useleaded fuel whena vehiclerequires unleadedfuel. The serviceindustry must be educatedto the requirementsof tuning for emissioncontrol rather than traditional performance and given sufficient incentivesuch as the mandatoryrequirement on their customersof passingan I/M testto providesuch tuning. The aftermarketservice and parts industry must be ableto providereplacement parts which do not adverselyaffect emissions performance.In addition,mqNures to preventintentional tampering with emissionscontrol systems must be undertaken. 118 Control measures and their effectiveness FueI hmposition Fuel compositionmay be controlled,as in the caseof unleadedfuel, for the purposeof propermaintenance, as discussedabove. In suchcases, control of fuel compositionis only indirectlya mqsure for controllingemissions. Fuel compositionmay alsobe controlledas the direct meansof controllingemissions, as is the casein reducingthe leadcontent of leadedgasoline to controllead emissions,or couldbe the casein reducingsulfur contentto controlsulfate emissions.lAlso, it shouldbe noted,unleaded gasoline lowers exhaust HC emissionscompared to the useof leadedfuel dueto changesin the characteristics of combustionchamber deposits. Recentstudies carried out in the UnitedStates by the autoand oil industries(the so calledAuto/Oil study)indicate that gasolinevehicle exhaust HC emissions decreasesignificantly with lower fuel sulfur. Dieselfuel generallycontains much higher levels of sulfur than gasoline. Therefore,many OECD (Organizationfor EconomicCooperation and Development)countries have decided to takesteps to lower the sulfur levelsas a strategyto reducediesel particulate emissions. This hasthe addedbenefit of increasingthe potentialfor catalyticcontrol of dieselparticulate and organic HC emissions. Controlof gasolinevolatility is anotherimportant strategy for reducingvehicle evaporativeand refueling emissions,especially in areaswith warmer climates. Experiencein the US indicatedthat whenlead in gasolinewas reducedduring the 1970'sand 1980's,highly volatilebutane components were added at leastin part to enhanceoctane levels, with the resultthat gasolinevolatility andevaporative, emissionsincreased significantly. Controlof fuel volatility is relatively inexpensiveand easilyaccomplished. It cangreatly lower vehicleevaporative emissionswhich accountfor roughly30 to 50Voof total vehicleHC emissions. Similarly, useof oxygenatedadditives in gasolinelowers exhaust HC andCO but shouldhave no effecton evaporativeemissions as long as fuel volatility is not IIt is worth notingthat eventhough an oxidationcatalyst may resultin slightly greaterconversion of sulfur oxidesto sulfate,all sulfur oxidesin the afinosphereare convertedto sulfates. So the useof catalystsdoes not resultin increasedsulfates considering the atmospherictransformation. Usually, the sulfur contentof gasolineis so low that gasolinefueled vehictes cause less than one percentof the sulfur oxidesin a givencountry. 119 Motor vehicle air pollution increased. Use of compoundssuch as methyl-tertiary-butyletherGvffBD do not increasefuel volatility; however,splash blending of alcoholssuch as ethanolcan increasevolatility. Conholling Vehicle Miles Travelled (VIvIf) Reductionof VMT is an additionalmeans of controllingemissions, e.g., through carpooling,increased use of masstransit, parking restrictions, gas rationing, etc. Exarples of suchstrategies include: 1. PoliciesTo InduceShifts To More EffrcientTransportation Modes Thasepolicies act to reducetransportation energy consumption and emissions per seatmile. Incentivesinclude transit fare reductionsand serviceimprovements, such as extendingcoverage, reducing headways, improving travel time and reliability of on-timeservice, coordinating transfers, and construction ofpark and ride facilities. Disincentivesusually fall on the privateautomobile in the form of increasedparking charges, surcharge taxes on motor fuel, andgasoline and diesel fuel rationing. 2. Policie.sto lncreasethe Load Factorof ExistingVehicle Fleets. Thesepolicies attempt to increasepassenger miles per seatmile. Incentives include carpool matchingand informationprograms, vanpool and commuterbus prograrns,dial a ride, shuttleand jitney services.Examples of disincentivesare similar to thosenoted above. 3. Policiesto Shift Time of PeakTravel DemandOccurrence. Thesepolicies work to decreasetransportation emissions per seatmile for all modesby spreadingcongasted peak traffrc loadsover a broadertime frameto improveuse patterns of existingtransportation capacity thereby improving vehicle operatingefficiency. Includedamong these policies are freeway ramp metering programs,fourday-work weeks,staggered work hours, and generaltraffic circulationimprovements, such as synchronizedsignals. 4. Policiesto ReduceTravel Demand Thesepolicies attempt to decreasepassenger miles through redistribution of urban activities. Examplesinclude land usepolicies to promotemixed land use,to increasedensity along transit corridors, and to coordinatenew subdivision developmentinto effrcientpatterns. An examplesof policiestaking advantage of new technologiasis the substitutionof communicationsfor transportationflows. r20 Control measuresand their effectiveness Thoughgenerally politically lessacceptable, such approaches tend to promotefuel conservation,can aid in urbanrenewal, and represent the only mobilesource controlmeasure remaining once vehicle control technology has been pushed to its limits. Whateversuccess is achievedin reducingper mile emissionsftom vehiclescan be eventuallyeroded by continuedhigh growth rates in the numberand use of vehicles. With very few exceptions(Singapore and Hong Kong beingamong the bright spots),transportation controls to reducethis growthhave been a failure, not becausethey cannotwork but ratherbecause most countries have not seriously tried to implementthem. It is now clearthat technologicalsolutions to the motor vehiclepollution problem are increasinglyoffset by growth in the vehiclepopulation. Therefore,long term solutionof the environmentproblem is dependenton comingto grips with the overallgrowth issue. High growth impactson emissionsin two ways. Not only doesit directly increaseemissions (more miles driven = more pollution),it leads to more congestionwhich further increasesemissions. Strateg5rEvaluation As the abovediscussion indicates, various enforcement tools are availableto addresseach stage of a vehicle'slife cycle. The certificationprocess which requirestesting of prototypecars prior to production,can affect vehicle design at low mileageand to a limited degree,the durabilityof emissioncontrols. Since certificationrequires reviews of a manufacturer'sproposed maintenance schedules, it may c.onstrainthe manufacturerfrom imposingthe necessarylevel of maintenanceand thereby reducethe potential effectivenessof recall and warranty. Someprototype maintenance nevertheless is not requiredto be recommendedto the consumer.Its major advantage,that it affectsvehicle design early in the designprocess before actual production begins, is alsoits major weakness,in that necessarily,it dealswith somewhatartificial, prototypecars in an artificial environment.By its very nature,therefore, it cannotaddress production problems,deterioration due to age,real world driving, ambientextremes nor the amountand quality of maintenancethat will actuallybe performedin-use. AssemblyLine Testingrequires testing of new productionvehicles and is the only techniquewhich can be usedto ensurebefore salethat vehicleswhen built are in fact meetingemission standards. However, its impacton durabilityof design dependson requiringallowances for deterioration,which are derivedfrom other programs,such as certificationor in-usetesting. Further,like certification,it cannotinfluence the amountor qualityof maintenanceperformed in-use. t2r Motor vehicle air pollution The recall andwarranty programs 2 canprovide some incentive to individualsto properlymaintain their vehiclesand are ftreonly programswhich candirectly affectthe actualin-use durability of vehicles. Theseprograms are subjectto the limitationsof dealingonly with properlymaintained vehicles and a generallyless thanperfect response on the part of individualvehicle owners, and they would appearonly to affect*rose vehicles which are likely to havebeen polluting excessivelyfor sometime. They representtherefore, remedies applied after considerabledamage has been done. Further, much of their potentialeffectiveness is lost after vehiclesare in-usemore thanone or two years. However,the major impactof thesemanufacturer directed in-use programs is a significantdeterrent to the designand/or manufacture of vehicleswhich will fail to complyinitially or as a resultof deteriorationfrom actualuse. I/M is the only compliancetechnique which ensuresthat in-usevehicles are properlymaintained. By requiringthat vehiclespass a retest,it directly influerrces the quantityand qualityof maintenancein additionto the design,through the warrantyand recall programs which useI/M as a surveillancetool. I/M is probablythe mosteffective "anti-tampering" program because of the intensivesurveillance built into the periodicinspection. such surveillanceis particularlyhelpful in addressingvehicle maladjustments which causevehicles to exceedstandards. However, where I/M is not in effect,gross tampering by dealersmay be discouragedby rigorousapplication of an "anti-tampering" program. The benefitsof I/M, however,are limited by the adequacyof the shorttest used, the ability of the serviceindustry to makeproper repairs and the potential tamperingwhich couldoccur following the testto allow the vehicle!o emit high emissionsthroughout the year. It seemsclear, therefore, that the idealprogram must include all of the above elements. 2Historically, in the US, thesehave applied to vehiclesfor five yearsor 50,000miles. However,in the 1990Amendments to the CleanAir Act, warranty liability was extendedto 8 yearsor 80,000miles for major emissioncontrol componentssuch as the catalytic converter,the electroniccontrol unit and the onboarddiagnostic controls; the warrantyfor all o0reremission control devices is reducedto 2 yearsor 24,000miles which evercomes first. Recallliability will be graduallyincreased to 10 yearsor l@,000 miles, with in userecall rcsting limited to 75,000miles. t22 Control measuresand their effectiveness Schedule/ Sequence In a perfectworld, with unlimitedresources, one might wish to implementall of the abovestrategies, simultaneously, at the very startof a program. This is very rarely, if ever, feasibleor practicaland could even be counterproductive. Therefore,it is necessaryto makedecisions about how to phasein the various strategies. One such approachis to devotethe early stagesof the program to laying a firm foundationfor further action. The first stepsare the adoptionof necessaryand feasible standards, widespread distribution of necessaryfuels, limiting the import of uncertifiedvehicles to individuals(rather than commercial companies),limited certificationand assemblyline testprograrns to ensure adequatevehicle designs, introduction of voluntaryI/M programs(which means every vehicle must be inspectedbut repair and retest is not yet mandatory),and the designand constructionof necessarygovernment testing facilities for future programs. In the secondphase, the requirementscan be graduallytightened. I/M should becomemandatory and the standardsmade progressively more sFingent, importationof non-certifiedcars restricted, and selectivegovernment testing used to verify certificationresults and institutenecessary recalls. Finally, as the fundamentalstructure gets accepted, it canbe graduallyand routinelytightened. For manufacturers,standards can be mademore stringentas technologyadvances, Recall liability andwarranty protection can be extendedto the actualvehicle lifetime, and allowablemaintenance requirements can be reduced. Fuelscan also continue to be improved. Onboarddiagnostics can be introducedon new carsand I/M programscan be modifiedto more fully utilize them. Vehicle Pollution Controls: The State of the Art Petrol Fueled Vehicles Significantprogress has occurred over the pasttwo decadesin the developmentof a wide variety of emissionsreduction technologies for petrol fueledvehicles. Beforecontrols were required, engine crankcases were verrted directly to the atmosphere.Crankcase emissions controls which basicallyconsist of closingthe crankcasevent port were introducedon new carsin the UnitedStates in the early 1960'swith the resultthat today,control of theseemissions is no longera serious concern. 123 Motor vehicle air pollution The hydrocarbonevaporative emissions result from distillationof fuel in the carburetorfloat bowl and evaporationof fuel in the gas tank. To control these emissions,manufacturers generally feed theseemissions back into the engineto be burnedalong with the otherfuel. Whenthe engineis not in operation,vapors iue stored,either in the enginecrankcase or in charcoalcanisters which havea strong affimty for theseemissions, and then burned off whenthe engineis started.3 Technologyto controlthese vapors is now readilyavailable but its overall effectivenessis dependenton the fuel volatility for which it has beendasigned. Exhaustemissions of hydrocarbons,carbon monoxide and nitrogenoxides are relatedto the airlfuel mixtureinjected, the peaktemperatures and pressures in eachcylinder, whether lead is addedto the petrol, combustionchamber geometry, and other enginedesign parameters. Variations in theseparameters ate, therefore, capableof causingsignificant increases or decreasesin theseemissions. The most importantparameters are probably air/fuel ratio and mixturepreparation, ignition timing, and combustionchamber design. Variationsin theseparameters are usuallykey elementsin vehiclecontrols when modest light duty vehicleemissions standardsare imposed. Dilution of the incoming chargehas beenshown to reducepeak cycle temperature by slowingflame speedand absorbingsome heat of combustion.Recirculating a portionof the exhaustgas back into the incomingair/fuel mixture (EGR)thereby loweringpeak cycle temperature is thereforeused to lower NO*. Improvementsin mixture preparation,injection systerns,and ignition systemscan increasedilution tolerance.This canalso be achievedby increasingthe burn rate or flame speedof the air-fuelcharge. Techniquesto do this includeincreased swirl andsquish, shorter flame paths, and multiple ignition sources. Electronics With so manyinterrelated engine design and operating variables playing an increasinglyimportant role in the modernengine, the control systemhas taken on increasedimportance. Modificationsin spark timing must be closely coordinated with air-fuel ratio changesand degreesof EGR lest significant fuel economyor performancepenalties result from emissionsreductions, or NO, emissionsincrease as CO goesdown. In addition,controls which canbe muchmore selective 3Suchan approachimproves vehicle fuel effrciencyas vaporspreviously releasedto the atmospherenow do work. t24 Control measuresand their effectiveness dependingon engineload or speedhave been found beneficial in preventing widespreadadverse impacts. Therefore,electronics have begun to replacemore traditionalmechanical controls. For exanple, electroniccontrol can optimize ignition timing under all engine conditionsand hasthe addedadvantage of reducedmaintenance and improved durability comparedwith mechanicalsystems. When coupledwith electronic control of EGR, it has beendemonstrated that NO* emissionscan be reducedwith no fuel economypenalty and in somecases with improvedfuel economy. Exhaust afrer-tr e atrnent d evi c e s When stringentexhaust emissions standards (especially hydrocarbons or nitrogen oxides) are madecompulsory, exhaust after-treatment devices such as catalytic converterstend to be usedto supplementengine modifications. An oxidationcatalyst is a devicewhich is placedon 0retailpipe of a car and which, if the chemistryand thermodynamics are favorable, will oxidizealmost all the HC and CO in the exhauststream. One of the uniqueadvantages of catalysts is their ability to selectivelyeliminate some of the more unhealthycompounds in vehicle exhaustsuch as aldehydes,reactive hydrocarbons and polynucleararomatic hydrocarbons. Three-waycatalysts (so calledbecause of their ability to lower HC, CO and NO. levels simultrnmusty) were first introducedin the United Statesin 1977by Volvo andsubsequently became widely usedwhen the US NO, standardwas loweredto 1.0 gramsper mile. To work effectively,thase catalysts require precise control of airlfuel mixtures. As a result, three way systemshave indirectly fostered improved air/fuel managementsystems such as advancedcarburetors and throttle body fuel injectionsystems as well as electroniccontrols. Startingwith 1975model year cars, catalysts have been placed on upwardsof 80 per cent of all new cars sold in ttre United States;in the last few years, either oxidation or three-waycatalysts have been placed on all new petrol fueled cars. In Japanand Canada,catalysts are alsowidely usedto meetemission standards. Many cars in Austria, the Netherlands,Sweden and Germanyare starting to be sold with thesesystems and they are required on new cars in Australia and Switzerland. SpecialProblems With Two-StrokeEngines Sincemany of the two-wheeledvehicles which are prevalentin manydeveloping countriesare poweredby two-strokeengines, a few specialcomments are in 125 Motor vehicle air pollution order. In general,most of the solutionsto reduceemissions from four-stroke enginescan be appliedto two-strokes.However, in addition,since much of the HC emittedcomes from lubricatingoil, this deservesspecial attention. "It is knownthat visible smokecan be reducedby the useof engineoils containing polyisobutylene,and also by leanerfuel oil ratios. Thereforethe separated lubricationsystem, which bringsabout overall leaner fuel/oil ratios,seems to be favorablefor smokereduction (Sugiura and Kagaya, L97i)." Further, 'since 1986,mopeds with catalystshave been available in Switzerlandand in Austria". Thesemopeds are requiredby law to complywith the stringentemissions standardsin thesecountries (Laimboch and Landerl, 1990). It is a fair conclusion to statetoday that the historicalproblems of high smokeand unburned hydrocarbonsfrom two-stroketechnology are no longertechnologically necessary. "New technologypromises to resolvethese concerns. As examples,direct cylinderelectronic fuel injection,electronic computer control, and catalytic exhaustconversion are now commonplacesolutions (lVyczalek, 1991)., It is worth notingthat moderntwo-stroke engines are emergingwhich are stafting to demonstratevery low emissions,excellent fuel economy,and low cost. Foremostamong these is the orbital Enginewhich hasundergone testing by the usEPA, andon at leastone modelappears close to achievingthe very stringent Ultra Low EmissionVehicle Standards of ttreState of California. OffRoad Vehiclesand Engines Recentstudies have indicated that vehiclesand enginesdesigned for useoff-road canbe importantsources of emissions.Such engines include the following: lawn andgarden equipment, airport service equipment, recreational equipment, light commercialequipment, industrial equipment, construction equipment, agricultural equipment,logging equipment and commercialmarine vessels. Both the USEPAand the california Air ResourcesBoard are in the processof developingstandards for someof thesesources. In additionthe European communityand the UN Economiccommission for Europeare in the processof investigatingproposals in this area. Diesel Fueled Vehictes While the majortechnical problems associated with reducingemissions frorn petrol c:us iue solved,it is apparentthat reductionsfrom thesevehiclqs alone are not sufficientto solvethe air pollutionproblems in manyareas. Dieseltrucks and buseshave therefore been receiving increased attention as significantsources of particulatesand No*. Emissionsdeterioration is very low for dieselvehicles comparedto petrol anddiesel vehicles have inherently low HC emissionsalthough 126 Control measuresand their effectiveness theseHC's arehigher in molecularweight and thus of a differentchafacter than thosefrom petrol engines. Further,uncontrolled diesel engines emit objectionable exhaustodors which are a frequentsource of complaintsfrom the public. The US hasadopted standards for thesevehicles which will fostertechnological developmentssimilar to thosewhich havealready occurred for petrol cars. These developmentsare receivingclose attention from other countries. Smokeemissions from dieselengines are composedprimarily of unburnedcarbon particlesfrom the fuel andusually result from an excessof fuel availablefor combustion.This conditionis mostlikely to occurunder high engineload conditionssuch as accelerationand enginelugging when the engineneeds additionalfuel for power. Further,a commonmaintenance error, failure to clean or replacea dirty air cleaner,may producehigh smokeemissions because it can chokeoff availableair to the engineresulting in a lower thanoptimum air-fuel mixture. Vehicleoperation can also be importantsince smoke emissions ftom dieselengines are minimizedby selectionof the propertransmission gear to keep the engineoperating at the mostefficient speeds. Moderate accelerations, lower highwaycruising speed as well as reducedspeed for hill climbingalso minimize smokeemissions. Basicapproaches to dieselengine emission control fall into threemajor categories: * enginemodifications, including combustion chamber configuration and design,fuel injectiontiming andpattern, turbocharging and EGR; * exhaustafter-treatment, including traps, trap oxidizersand catalysts;and * fuel modifications,including control of fuel properties,fuel additive'sand alternativefuels. NO* controltechniques being phased into the dieselpopulation include variable injectiontiming andpressure, charge cooling, and EGR. Retardinginjection timing, while a well knownmethod of reducingNO, formation,can lead to increasesin fuel consumption,and particulate and hydrocarbon emissiorrs. These problemscan be mitigatedby varyingthe injectiontiming with engineload or speed. Also, high pressureinjection can reduce these problems. If coupledwith electroniccontrols, it appearsthat NO, emissionscould be reducedsignificantly with a simultaneousimprovement in fuel economy(although not as great as would occur if electronicswere addedwithout any emissionrequirements). With relativelylenient particulate standards, engine modifications are generally sufficientto lower engine-outemission levels. They includechanges in combustionchamber design, fuel injectiontiming andspray pattern, 127 Motor vehicle air pollution turbocharging,and the useof EGR. Furtherparticulate controls appear possible throughgreater use of electronicallycontrolled fuel injectionwhich is currently underrapid development.Using sucha system,signals proportional to fuel rate andpiston advance position are measuredby sensorsand are electronically processedby the electroniccontrol system to determinethe optimumair fuel ratio and timing. Oneof the importantfactors in dieselcontrol design is that NO*, particulateand hydrocarbonemissions are closelyinterdependent. For example,retarded timing within certain rangesdecreases NO* and particulatesbut can lead to increasesin HC. As technologyhas advanced, these potential trade-offs have diminished. For example,certain new enginedesigns (combustion chamber modifications, electronicallycontrolled fuel injection,etc.) haveresulted in simultaneous reductionin HC, particulatesand NO*. Exhaustafter-treatment methods include traps, trap oxidizers, and catalysts. Trap oxidizerprototype systems have shown thernselves capable of70 to 90 percent reductionsfrom engine-outparticulate emissions rates and with proper regeneration,the ability to achievethese rates for high mileage. Basicallyall rely on trappinga major portionof the engine-outparticles and consumingthem before they accumulatesufficiently to saturatethe filter andcause problems, such as increasedfuel consumptionand reducedperformance. Worldwide Progress In Lowering Vehicle F'.missions Advancesin automotivetechnologies have made it possibleto dramaticallylower emissionsfrom motor velricles. Increasingly,countries around the world have beentaking advantage of them. Initial crankcaseHC controlswere first '60's introducedin the early followed by exhaustCo and HC standardslater that decade.By the early to mid 1970's,most major industrialcountries had initiated somelevel of vehiclepollution control progr:rm. For a varietyof reasons-- differing typesand degrees of air pollutionproblems, varying vehicle characteristics,economic conditions, etc. .- the emissionscontrol approaches differ significantly betweencountries. Petrol Vehicles Japan and fiu AS During the mid to late 1970's,advanced technologies were introducedon most new carsin the US andJapan. Thesetechnologies resulted from a conscious decisionto "forcenthe developmentof new approachesand were ableto dramaticallyreduce CO, HC and NQ emissionsbelow levelsachieved by 128 Control measures and their effectiveness previoussystems. As knowledgeof thesetechnological developments on cars spread,and as the adverseeffecS of motor vehicle pollution becamemore widely recognized,more andmore peopleacross the globebegan demanding the useof thesesystems in their countries. 'Western Europe During the mid 1980's,Austria, the Netherlandsand the FederalRepublic of Germanyadopted innovative economic incentive approaches to encouragepurchase of low pollutionvehicles. Sincethen, Australia,Austria, Canada, Denmark, Finland,Norway, Swedenand Switzerland have all decidedto adoptmandatory requirements. Within the EuropeanCommunity, at the EuropeanCouncil of Environmental Ministersmeeting on 12 June1991, there was unanimous agreement to adoptthe 199211993auto standards provisions which havebeen on the tableover the last few yearsalong with an additiondstep to be introducedin approximately1996. However,the detailsof the "secondstep" will needto awaitsubsequent action sincethe EuropeanParliament was unable to mustersuffrcient votes to resolvethe question. Specificallythe Ministersdecided to: l. Requireall new modelsof light duty vehiclesby July 1992nd all new cars after 1 January1993 to meetemission standards roughly equivalent to US 1987levels Q.72 elkmCO, 0.97g/km of HC plusNO,,, 0.14 g/km of particulatesfor Type Approval,3.16 g/km CO, 1.13g/km for HC plus NO*, 0.18 g/km particulatesfor Conformityof Production), 2. Requirethe Commissionto developa proposalbefore 3t December1992 which, taking accountof technicalprogress, will requirea further reduction in limit values, 3. To havethe Councildecide before 3l December1993 on the standards proposedby the Commission,and 4. Prior to 1996,to encouragethe introductionin all countries,of tax systemsin which pollutantsand other substancesform the basisfor calculatingmotor vehiclecirculation taxes. Rapidly htdustrializing C.ountries Even rapidly industrializing,developing countries such as Brazil, Mexico, South Koreaand Taiwan have adopted stringent emissions regulations. Most recently, during 1990,such requirements have spread to Chile, Hong Kong andSingapore. r29 Motor vehicle air pollution Adoptionof currentstate of the art emissionsstandards has been demonstrated to substantiallylower emissions.For example,in ttre Unitedstates today, cars exhaustless than 20 percentof the hydrocarbonsand carbon monoxide per mile driven thanuncontrolled vehicles did in the 1960's. studiesconducted by a major US car manufacturerindicate that the effectivenessof emissioncontrol svstems continuesto improve: In summary,the in-useexhaust emission performance has improved substantiallysince the introductionof computercontrolled closed-loop systems in 1981. GM's 1986model year performance is below the Federalstandards, on average,at 50,000miles. Additionalimprovements, especially for CO, are desired. Heavy Duty Trucls, Busesand Diesels Thereare various problems associated with dieselsmoke and particulate, for which controlprograms have been underway for manyyears. The next section will reviewthe history of theseprograms to date. In general,the initial focuswas on smokecontrol because it was clearlyvisible anda nuisance.As the evidence has grown in recentyears regarding the serioushealth and environmentalrisks of dieselexhausts, more attentionhas focused on controlof the particlesthemselves. while smokestandards lower visible smoke,they are not as effectiveat lowering particulateemissions as particulatestandards are. That is, thereis somebut not completecorrelation between visible smokeand particulate. Smokestandards are designedto addressvisibility problemsand particulate standards are designedto achieveacceptable ambient particulate levels. United States us emissioncontrol requirements for smokefrom enginesused in heavyduty trucksand buses were first implementedfor the 1970model year. Theseopacity standardswere specifiedin termsof percentof light allowedto be blockedby the smokein the dieselexhaust (as determined by a light extinctionmeter). Heavy duty dieselengines produced during modelyears 1970 through 1973 were allowed a light extinctionof 40 percentduring the accelerationphase of the certification testand 20 percentduring the luggingportion; 1974and later modelyears are subjectto smokeopacity standards of 20 percentduring acceleration,15 percent during lugging,and 50 percentat maximumpower. The first dieselexhaust particulate standards in the world were establishedfor cars andhght trucksby the USEPAon 5 March 1980. standardsof 0.6 gramsper mile (0.37 g/km) wereset for all carsand light rrucksstarting with the 19g2 modelyear droppingto 0.2 gramsper mile (0.12 g/km) and 0.26 (0.16) for l9s5 130 Control measuresand their effectiveness modelyear carsand light trucks, respectively.In early 1984,USEPA delayed the secondphase of the standardsfrom the 1985to 1987model year to providemore time for manufacturersto comply. Almost simultaneously,California decided to adoptits own dieselparticulate standards - 0.4 gramsper mile (0.25 g/km) in 1985,0.2(0.12) in 1986and 1987, and 0.08 (0.05) in 1989. Particulatestandards for heavyduty dieselengines were promulgated by the USEPAin March, 1985. Standardsof 0.60 gramsper Brake- Horsepower- Hour (g/bhph)(0.80 gramsper kilowatt-hour)were adoptedfor 1988through 1990model years, 0.25 (0.34)for l99l through1993 model years and 0.10 (0.13) for 1994and later modelyears. Becauseof the specialneed for bus controlin urbanareas, the 0.10 (0.13)standard for thesevehicles will go into effectin 1993, andthen be cut by an additional50% oneyear later. Subsequently,USEPA revised the 0.26 gramsper mile dieselparticulate standard for certainlightduty trucks. Lightduty dieseltrucks (LDDTs) with a loaded vehicleweight of 3751pounds or greater,otherwise known as LDDT2s, were requiredto meeta 0.50 gramsper mile standardfor 1987and 0.45 gramsper mile level for 1988-1990.For the 1991and later modelyears the standardwas tightenedto 0.13 gramsper mile. It is worth notingthat the driving force behindttre controlof particulateemissions from vehiclesin the US hasbeen the adverseimpacts of particleson mortalityand morbidity. While concernshave existed regarding potential carcinogenic effects from exposureto dieselexhaust, this hasnot yet beenthe basisfor regulationof theseemissions. Canada In March of 1985,in parallelwith a significanttightening of gaseousemissions standards,Canada adopted the USEPAparticulate standards for carsand light trucl$ (0.2 and0.26 gramsper mile, respectively)to go into effect in the 1988 modelyear. Sincethen, Canadaalso decided to adoptUSEPA standards for heavyduty vehiclesfor 1988as well. Canadaintends to closelymonitor developmentsin the US as 1994approaches; if technologyadvances sufficiently, andif the US retainsis existingstandards, it appearslikely that Canadawill adopt them. Japan Smokestandards have applied to both new andin-use vehicles since 1972and, 1975,respectively. The maximumpermissible limits for both are50 percent opacity;however, the new vehiclestandard is the more stringentbecause smoke is 13r Motor vehicle air pollution measuredat full load, while in-usevehicles are requiredto meetstandards under the lesssevere no-load acceleration test. Recently,after a lengthyprocess of internaldebate and discussion, the Ministry of Transporthas issued a reporton and a plan for dealingwith dieselparticulate and nitrogenoxide emissions.It includesboth a shortterm and a long term set of standards. Also includedin the strategydocument is the adoptionof a high speeddriving cyclefor all light duty vehiclecategories. EuropeanCommunity Smokelimits similarto thosedescribed above in the UnitedStates and Japan have beenin effectin Europefor manyyears. Exhaustsmoke levels are currently recommendedby EEC Regulation24 (equivalentto EEC Directive721306). Measurementsare taken using light absorptiontype apparatus. However,recognizing the inadequacyof theserequirements, the European CommunityEnvironmental Ministers decided in December1987 to adopta particulatestandard for light duty diesels. First stagerequirements have now been introducedand will be graduallytightened throughout the 1990's. At presentthere is no particulateemissions legislation in force for heavyduty enginesin the EC. Commentingon this, the Houseof Lords (UK) Select Committeeon the EuropeanCommunities issued a reporton "Particulate EmissionsFrom Diesel-Enginedcars", basedon evidencegathered during 1987in which they concludedthat "The Committeeare impressedby the evidencethey havereceived which suggeststhat the environmentalbenefits of the proposal[regarding particulate emissionsfrom dieselcars in the CommonMarketl will be negligible. They agreewith thosewitnesses who describedit as doing little morethan maintainingthe environmentalstatus quo...The committee believe ttrat until legislationis introducedto controlparticulate emissions from largedie,sel- enginedvehicles, the main environmentalimpact of dieselvehicles will be unalleviated." In responsea proposalwas developed and at the I october 1991meeting of the Councilof EnvironmentalMinisters, final agreementwas reached on the Directive !o tightenheavy duty vehicleemission standards. The "cleanlorry" directivefixes EEC normswhich will be compulsorythroughout the EC (not optional),in two stages: r32 Control measuresand their effectiveness 1) After I July 1992,new typesof dieselengines and diesel-fuel vehicles will haveto respectthe following nonns: - qubon monoxide(CO g/kwh = 4.5); - hydrocarbons(HC g/kWh = 1.1); - nitrogenoxides (NOx g/kWh = 8), and - particulatesaccording to engine-power: lessthan 85 kW (PT g/kWh = 0.63), or more than 85 kW (PT g/kwh = 0.36). Accordingto the EuropeanCommission, the vehicleindustry is alreadygetting readyto ensureconformity to thesenorms for mostvehicle models. 2\ After 1 October1995, the new dieselengines and vehicles will haveto complywith the following standards: - carbonmonoxide exhaust (CO g/kWh = 4); - hydrocarbons(HC g/kWh : 1.1); - nitrogenoxide (NO* g/kWh = 7), and - particulateemissions (Pf g/kwh = 0.2). Non-EC CountriesIn WesternEurope Severalother European countries have been cooperatively moving toward more significantdiesel particulate requirements. Sweden has already adopted the US- EPA passengercar standardto go into effectin 1989and Switzerland and Austria arelikely to do so in the nearfuture. In Austria,a maximumpermissible limit for particulateemissions of 0.373g/km (0.6 gramsper mile) is alreadyprescribed. On the 4 May 1988the Swissgovernment introduced new emissionstandards for heavyduty vehiclesto go into effecton I October1991; they includestandards for CO, NO* andVOC as well as for particulates.The standards,based on the EuropeanRegulation ECE R 49, ue as follows: PresentStandards Prior Standards by I Oct. 1991 as of 1 Oct. 1989 co 4.9 g/kWh 8.4 g/kWh voc r.23 g/kWh 2.1 g/kWh Nox 9.0 g/kWh t!:! g/kwh Particulates 0.7 g/kWh The new standardsare about40 percentlower thanthe former onesfor heavy dieselvehicles. However,it is intendedto tightenthese standards again in the early ninetiesto meetthe stringentUSEPA 1994standards. 133 Motor vehicle air pollution on 2 February1988 the Swissgovernment decided to set new emissionstandards for molorcyclesto go into effectby october 1990. The,seprescriptions focused mainly on voc controlfor two-strokeengines, whereas the standardsfor four- strokemotorcycles remain unchanged. Standardsas of 1 Oct. 1990 Prior Standards two-strokeengines two-stroke four-stroke co 8.0 g/km 8.0 g/km 13.0 g/km voc 3.0 glkm 7.5 glkm 3.0 g/km No- 0.1 g/km 0.1 g/km 0.3 g/km During the padiamentarydiscussion of summer1987 on the air pollutioncontrol strategyit wasrecognized that the measuresundertaken so far are only sufficient to reachthe goalsset for SQ but not for NO* and VOCs. Thereforethe Parliamentcalled for an additionalseries for 54 measuresto be quantifiedwith the aim of achievingthe reductionsfor No* andvoc emissions.The first part of ttre report showedthat with the projectedtechnical measures, the desiredreduction cannotbe achievedand various policy measures,e.g. traffrc management,have to be studied. within this contextthere are discussionsgoing on regardingthe waysto reduce evaporativelosses of VOC from solventuse in industrialprocesses and from transportand distribution of petrol. Virtually all stationsnow sell 95 RON unleadedpetrol at this time with unleadedfuel approximately8vo less than leaded. on october 1, 1989the dieselparticulate standard for all new carswas reduced from 0.37 gramsper kilometerto 0.124. Also on Octoberl, 1989the first step of the stockholmGroup light duty truck standardswent into effect;the second stepstarted on I october 1990. The first stepofthe heavyduty standardswas introducedon 1 october 1988. The secondstep which includesthe first European truck particulatestandard (0.7 gramsper kilometer)and is intendedoverall to be approximatelyequivalent to ttre 1990US standardsalthough based on the European13 modetest went into effecton I october 1991. Finally, a third step is beingplanned for the mid 1990'sthat will be equivalentto1994 USEPA standards(also likely includingtrap oxidizersor catalysts). Swissofficials havereceived a mandatefrom their governmentto explorethe feasibilityof adoptingthe california autostandards - 0.15 g/km non-methaneHC, and0.25 g/km nitrogenoxides. simultaneously,they continueto explorea third stepfor heavyduty vehicles,intending to adopistandards equivalentio usEpA 1994requirements by 1995or 1996. In conjunctionwith theserequirements, they intendto reducediesel firel sulfur levelsto 0.05 Wt. %, perhapsas early as 1 January1994. Thesecountries are alsolooking hard at more stringent 134 Control measuresand their effectiveness requirementsfor trucksand buses. Swedenhas announced its intentionto adopt requirementsthat will bring aboutthe samedegree of controlas the US by 1995. Specifically,USEPA 1990requirements (including diesel particulate) were adopted by Swedenon a voluntarybasis for 1990light duty trucks, andmade mandatory for 1992. Regardingheavy trucks, Swedenintends to strivefor vehicle technologyand the equivalentenvironmental benefits as in the US. The standards werevoluntary from 1991but will be mandatorystarting in 1995. For Europeas a whole, therefore,the heavyduty vehicleemissions picture can be summarizedas follows: Summaryof Europeanheavyduty dieselrequirements (Current Status) Units (g/kwh) co NO* PART SwitzerlandStep 1 (Oct. 89) AustriaStep 1 (Jan.88) 8.4 2.1 14.4 Switzerland-Step2 (Oct. 91) Austria-Step2 (Oct. 91) 4.9 1.23 9.0 0.7 Sweden- 93 MY (A-30) Norwav - Oct. 93 4.9 1.23 7.0 (0.35or 0.4) EC-SteplType 4.5 1.1 8.0 0.63 Approval 0.36 coP (4.e) (r.23) (9.0) (0.7X<85Kw) (0.4)(>85 Kw) SwitzerlandStep 3 (4.e) (r.23) (e.0) (0.4) EC Step2 4.0 1.1 7.0 0.15 (Also Likely SwissStep 4) EC Step3 (2000) New test or later possible r35 Motor vehicle air pollution Future Prospects For Vehicle Trends The growth in demandfor motorizedtravel is well understood.As urbanareas populateand expand,land which is generallyat the edgesof the urbanarea and previouslyconsidered unsuitable for habitationis developed.Also the high costof housingin the city centersforces people to pursueaffordable housing in the suburbanareas. As the distanceof theseresidential locations from the city center or other subcentersincreases, so doesthe needfor motorizedtravel. Motorized travel often in privatevehicles supplants traditional modes of travel suchas walking, variousbicycle forms, watertravel, and evenpublic transport. The need for privatevehicles is reinforcedas decliningpopulation and employmentdensities with distancesfrom urbancenters reduce the economicviability of public transport. The evolutionof urbanareas is influencedby the growthof incomeand accompanyingincreases in the acquisitionsof privatemotor vehiclesand changes in travel habits. As incomesrise, an increasingproportion of trips shifu, first to motorcyclesand, as incomeincreases further, to privatecars. The trend toward privatemotorization is alsoinfluenced by public policy towardsland use,housing, andtransportation infrastructure. While the proportionof middle andupper incomehouseholds in developingand newly industrializedcountries able to afford carsand motorcycles is lower than in industrializednations, the numberof private vehiclesstill becomesvery largeas the middleand upper income groups grow in megacities.The numberof vehiclesand levels of congestionare comparableto or exceedthat of major citiesin industrializedcountries. With the increasein motorizedtravel and congestioncome increases in energyuse, emissionsand air pollutionCIDRI, 1990). Projectionsof populationtrends for the future in mostrapidly industrializing countriesindicate both rapid populationgrowth and increasingurbanization ofthat population. In short,these trends generally increase the geographicalspread of cities,both largeand small, increasingthe needfor motorizedtransit to carry out an increasingportion of daily activities. Further, whencoupled with expanding economiesas is increasinglythe casein thesecountries, a greaterproportion of the urbanpopulation can afford personalmotorized transportation, starting with motorcyclesand progressing as soonas economicallyfeasible, to cars. In summary,therefore, in comingyears, under current policies one canexpect manymore citizensof developingcountries to be living in larger andlarger cities anddriving more andmore privatevehicles. As a result,without intervention, today'salready serious pollution problems are likely to worsen,exposing greater numbersof peopleto evenhigher pollution for longerperiods of time. 136 Control measures and their effectiveness REIIERTNCES Laimboch and Landerl. 50cc Two-StrolceEngines for Mopeds, Chainsawsand Motorcycleswith Catalysts.SAE 901598(September 1990). Sugiuraand Kagaya. A Studyof Visible SmokcReduaionfrom a Small Two- StrokzEngine Using Various Lubricants. SAE 770623(June 1977). TDRI. The rcm TDN YearEnd C.onference,Industrializing ThailandAnd. hs Impaa On TheEnvirownent, Research Report No. 7, Energyand Environment: ChoosingThe Right Mix @ecember1990). Wyczalek. Two-StrolceEngine Technology in the 19X)'s. Containedin SP-849, Two-StrokeEngine Design and Development. SAE 910663(March 1991). t37 Chapter5 CASE STI]DIES OF MOTOR VEIIICLE FOLLUTION IN CITIES AROUND THE WORLD DavidT. Mage'andMichael P. Walsh** The Urban Environment In Developing Countris: Examples From Asia As a resultof the large andgrowing population of poorly maintainedvehicles with minimal, if any, pollutioncontrols and powered by unusuallydirty fuels, most major citiesof Asia are alreadyexperiencing serious motor vehiclerelated air pollutionproblems, frequently on top of other seriousenvironmental insults. In virually everycrty for which datais available,co, leadand particulate levels are the primary pollutantscausing these problems. Furthermore,vehicles contribute significantamounts of HC andNQ emissionswhich are frequentlytoxic and contributeto photochemicalsmog in cities with the appropriatemeteorological conditions. * David T. Mage, Scientist,World HealthOrganization, Geneva, Switzerland. " MichaelP. Walsh, Consultant,Arlington, Virginia, UnitedStates of America. 139 Motor vehicle air pollution ...i...,.'.llvlo.iltoting..dtta..Chow..$+{..aii...qualiry..in,Siilgr€;,,,Banlkok,,Manild;, : and rakarta are not at*ays acceptabteaccording to thb country's ambientair quality sandards.":The pollutantsof concernare directly or .. indiiectly causedby motorvehicles, They |re suspendedparticulate ,, mtuers (SP$; Car-bq*mbnoxide(CO) andlead. LCvelsof CO were i..t..,iiiifGrt ...fi...be..as...high...as.i.95...ppi..!il...Ja*l'rs't..49.i.BpRi..in..H .:Yai'i.(clty i .1.1,;,.,.iin.iei:.s6 ,.of..i|htmA)...0n.....l... ,.,anffie:..i.'.. c.. fidfi..dn.. i:il:i:::idr*[:ippllluffil:lu$Ufiryllleffii:ie:l.ffibieilti*Fllqudi$iii udsl:*#; ' ,, , .,,..bttnt'n'*ufednear,roadwtt'rt,,,,. , , 1...,..S:0ui'ce:...'i.'1t:'.!Aii.1P'1ution..P.iobr.1$..bid',Manag.e.nent:i..ih:!Asian]:i:::]i::.:::::: .. ' 'Countriest;::KirtVanichr,,ranicfi : , am Middfeton;Air ". ',, '. : :::PoitutibnCdntrofAsociation Paper 8G33,+, June 19t6, For example,in Thailand,the Office of the NationalEnvironment Board has monitoredlevels of carbonmonoxide, particulate matter and lead near major roads in Bangkoksince 1984. Accordingto their latestannual report (National EnvironmentBoard of Thailand,1990) "the air pollutionproblem in Thailandis seriousnear the major streets." In certainareas of the city wheretraffic is heavy, "particulatematter's concentrations far exceedthe daily ambientair quality standardsof 330 microgram/cubicmeter on any day, and are as high as 2-3 times standardvalues on somedays." Carbonmonoxide levels are alsohigh in some congestedareas, also exceeding air qualitystandards. A studyof blood leadlevels of policemenat threedifferent rates of exposureto vehiculartraffrc, found a positivestatistically significant link betweentrafftc exposureand blood leadlevels @aungchat, undated). While reporteOblood lead bveti are somerrhatinconsistent Gtudy ,resultsrange ftom 160to 4O0pg:per tiiei), eventhe lowestreported ad,.in and ..i....tteiase....ili{rt*.,mi*...as....$eat...ru'..th.. t}reUnited States 1rm Casestudies of cities around the world Otherair pollutantssuch as nitrogendioxide and ozone from photochemical oxidantreactions are found to be still at low levelsin the city dueto the favorable meteorologicalconditions of Bangkok,with prevailingseasonal monsoon winds and seabrwze. The noisepollution problem in Bangkokis alsosevere and is causedmainly by traffic. Data collectedalongside densely travelled roads were found to have EquivalentSound Levels Grq) for 24 hours of 75 to 80 dB, much greaterthan the US EnvironmentalProtection Agency's (USEPA) recommended 70 dB for long term hearingprotection (National Environment Board of Thailand,1990). The percentageofmotor vehiclesexceeding a noisestandard of 100dB (A) at a distanceof 0.5 metersare summarizedbelow. Site Motor Diesel Mini- Bus Truck Motor Cycles Cars Buses Tricycle A 2t.4 5.3 8l B 5.9 JJ.J 81.8 68.1 c 6.0 20.0 78.6 90.7 86.8 70.0 D 3.1 5.6 33.3 88.6 60.0 13.3 E 10.2 4t.4 82.4 88.0 F 5.4 30.8 84.8 72.5 G 9.4 H 6.7 20.0 ,10.5 77.8 62.7 I 7.5 16.7 27.6 80.9 77.4 J 5.1 63.3 141 Motor vehicleair pollution As the abovedata shows, significant numbers of all vehiclecategories tend to be very noisybut the problemis especiallywidespread with trucksand buses. '1.5 In Hong Kong, approximately to 2 million peopleare exposedto unacceptablelevels of sulfur dioxideand nitrogen dioxide and aboutthree million peopleare exposedto high particulatelevels. Many peopleare exposedto unacceptablelevels of all threepollutants" (Hong Kong EPA, 1989). Air quality exposureproblems associated with the transportsector are summarized in Chapter3. The adverseeffects of this pollutionare summarizedin Chapter2. "The most commonadverse health effects of thesepollutants take the form of increasedincidence of respiratoryillnesses, such as asthmaand bronchitis. The high levelsof air pollutionin manyparts of Hong Kong mustseriously aggravate the conditionof thosealready suffering from suchillnesses and contributeto the onsetof chronicconditions. Other health effects such as lung cancercan be causedby air pollution, as certainair pollutants,such as thoseemitted from diesel vehicles,are knownto be carcinogenic"(Hong Kong EPA, 1989). The World Healttrorganization's International Agency for Researchon cancer (IARC) has evaluatedthe carcinogenicrisk to humansof exposureto dieselengine exhaust and concludedthat dieselengine exhaust is "probablycarcinogenic to humans'l. The air pollutionproblem in manyurban areas is compoundedby the life style and climatein manyof the warmerAsian cities. As a result,and as pointedout in chapter3, thereis muchgreater public exposureto the emissionsfrom vehicles which are emitteddirectly into the breathingzones of manymillions of people. Quantiffingthe costsof air pollution is very difficult. A recentstudy carried out for the AmericanLung Associationconcluded that "Nationalhealth costs worth between$4.43 billion and $93.49billion per yeardue to automotiveand truck exhaustpollution could be avoided"(American Lung Association,1990). I rhe InternationalProgramme on chemicalSafety, a cooperativeprogramme of ILO, UNEP, andWHO is in the processof assessingthe humanhealth and ecotoxicrisks of motor vehiclefuels (petrol,diesel, alcohols) and exhaust emissions.The assessmentwill includefuels and exhaustemissions as complex mixtureswith considerationof importantchemical constituents. r42 Case studies of cities around the world "Althoughit is impossibleto be precise,hundreds of millioru of dollars are spentevery year on combatingair pollutionor payingto rectify its effects. This expenditurearises in manydifferent ways, from the obvious,such as maintainingthe EPD's [EnvironmentalProtection Departmentlair controlstaff and equipment,to the lessobvious, such as the costto the public of maintainingmore hospital'b'eds and medical staff, the costof cleaningbuildings and clothesmore frequently and the costof replacingor repairingequipment or partsof building5or other structuresthat havebeen severely corroded as a resultof the aCidic propertiesof somepollutants. Considerableexpenditure is also incurred by industrialissand tle governmentin minimizingair pollution' sometimes,becauseof the inappropriatesiting of industrialor residential buildings." Source: "WhitePaper: Pollution in HongKong - A TimeTo Act"; What is Being Done To Address The Problems Chapter4 summarizedthe statusof technologiesand other strategiescurrently availableto reducevehicle emissions. In spiteof the low pollutiontechnological advanceswhich are now readilyavailable, several countries in Asia haveonly beenable to makelimited progressin reducingvehicle emissions. Prospectsare not entirelybleak. Rapidlyindustrializing areas such as Taipei and Seoulhave recently introducedstate of the art controls on new petrol cars and are rapidly puttingcomprehensive vehicle control programs in place. Decisionshave beenmade to do the samein Hong Kong andSingapore, and Thailand appears on the vergeof following suit shortly. Unleadedpetrol andlow leadedpetrol which hasbeen relatively rare in muchof the regionis startingto spreadrapidly and is eitheralready available or is likely to be soonin Japan,Taipei, Korea, Hong Kong, Singapore,Malaysia, Indonesia and Thailand. Motorcyclesin Taipeiwill be subjectto the moststringent motorcycle standards in the world, in a few monthsand a promisingdevelopment for other citiesin the regionwith similar two-strokemotorcycle problems. In manyparu of the regionhowever economic or other conditionsappear to constrainthe possibilityof progressin the shortterm. In comingyears, under currentpolicies it is expectedthat manymore Asianswill be living in larger and larger citiesand driving more andmore privatevehicles. As a result,without 143 Motor vehicle air pollution intervention,today's already serious pollution problems are likely to worsen, exposinggreater numbers ofpeople to evenhigher pollution for longerperiods of time. BecauseBangkok already exceeds WHO guidelinesfor air pollution, certainlyin rfgards to CO andSPM, andmost likely in termsof lead, it may be concludedfrom theseresults tlat air pollutionby the year2006 will more regularlyeiceed acceptatle levels. Higher peak conceDtrationswill occurover a broadergeographic area for a much largerexposed populaiion. Only the adoptionof pollutionlimiting pgliCieswill preventthis from happening. :::::. Source:TDRI ResearchReport No. 7 Definition of the Problem: A Case Study of Manila philippines, Manila, the capitalof the is at Latitude 14o36'N andLongitude l20o 59' E alongthe shoreof lvlanilaBay on the westside of Luzon island. The city 1$ the heavilypopulated surrounding areas, form a megalopoliscalled MetropolitanManila, or the Nationalcapital RegiontNcn). Industrial developmentof the Philippinesis centeredin Manila, which is the country,s internationalport of commerce.Metropolitan Manila is essentiallvat sealevel and occupiesapproximately 636 km2of land on the deltaicptain of the pasig River, which flows from Lagunade Bay, a lake to the southeastof the city, into Manila Bay. The populationof MetropoliranManila has expanded rapidly from 5.9 million in 1980to 7.0 million in 1985and is estimatedto be g mi[ion at present. It is projected(uN astimate)to grow to l l.1 million by the year20010. tn 19g0, approximately64vo of the 48 million Filipinoslived in rural areas,Manila being the country'schief urbanpopulation center with l2vo of the country,spopulation. The populationdensity of Metro Manila is approximately12 600 persons'pertm2. Sinceworld war II, the per capitaGNp of ttrephilippines has risen rapidly to its present(1990) level of $630(us); as the commercialand economiccenter of the countryit is expectedthat the per capitaGNp within Manila would be higher. r44 Casestudies of cities around the world Privatemotor vehiclesare primarily petrol fueled. Taxis,jeepneys and buses primarily fueledby dieselprovide public transportationin MetropolitanManila. Railways connectManila to northern and southeasternsections of Luzon, and a light rail transportsystem transports some 350,000 people per working day ttrrough30 km of rail system. Most vehiclesare privatepassenger vehicles, taxis or motorcycles.Of the 510,000vehicle registrations in 1988for petrol anddiesel vehicles,approximately 383 000 (or 75%) arepetrol fueled. The numberof motor vehiclesis expandingat a far greaterrate than the roadwaysystem can absorb. In a recentperiod when the numberof newly registeredcars increased by 53% , utility vehiclesby 44Voand trucks by 29%, the lengthof roadways increasedby 0.4Vo. Estimatesof vehicleemissions have been tabulated for 1988by the Philippine EnvironmentalManagement Bureau (EMB). The EMB estimatesindicate that petrol fueledvehicles contribute about70% more total organicgases (tOG) than dieselvehicles, while petrol poweredvehicles emit about16.5 times the massof CO emittedfrom dieselvehicles. The majorityof SO, andparticulate matter emittedby vehiclescome from the dieseltypes, while NQ emissionsfrom diesel vehiclesare aboutthree times those from petroltypes. Utility vehicles,most of which arediesel powered jeepneys, account for morethan half the particulate matter@M) andSO,, and abouthalf of vehicularTOG and NO* emissions. Otheremissions include lead, all of which is eminedby petrol poweredvehicles. The highly visible black smokeemitted ftom dieselvehicles is a very significant problemin Manila as passengersand pedestrians are often exposedto the undilutedexhaust. Thereare major questions,however, as to the accuracyof the emissionsfaclors usedin the EMB inventory,due largely to the lack of emissionsdata on vehicles as operatedin the Philippines.Contributing factors include observations that vehiclemaintenance is generallyinadequate and petrol poweredvehicles have no emissioncontrols. Thejeepney diesel engines are often importedfrom Japanafter their economicallyuseful life is over andrebuilt or reconditionedfor usein the Philippines. Their emissionfactors are unknown. t45 Motor vehicle air pollution kposure Measurements Exposuresto automotivepollutants had neverbeen measured until recently,when subida,Torres et al. (1991)performed an epidemiologicalstudy of illnessamong jeepney drivers, air conditionedbus driversand commuters(see also chapter 3). The studyreported human exposure data, obtained by personalmonitoring to the pollutantsso2, TsP, co andPb. Thesevalues are wel abovewHo guidelines for thesepollutants and are indicative of the severity of the automotiveexposures of peoplewho haveoccupational contacts and the potentialfor developmentof chronicconditions from long term exposures. The resultsof the epidemiologystudy, with correctionsfor smokingand other covariates,show tlrat thejeepney drivers with their high exposureshaue a much higherodds ratio of 2.3 for havingchronic obstructive pulmonary disease (copD) as comparedto the bus driversand commuters.Also they havemuch reduced pulmonaryfunction. As a resultof this study,it appearsthat automotiveair pollutionhas profound implications for the healthof the urbanpopulation and showsthe needfor developmentof an effective control progr:rmto timit automotiveemissions. The problemis complicatedby economicconsiderations which leadto the useof second-handimported diesel engines in thejeepneys and of highly pollutingvehicle power systems. A Case Study of Mexico City, DF The numberof automobilesin Mexico city hasgrown dramaticallyin the past severaldecades; there were approximately 48,000 cars in 1940,640,000 in t920, 1.1 million in 1975and three million in 1985. The Mexicangovernment estimates that fewer thanhalf of theseqrs are fitted wittr evenmodest pollution control devices. virtually none are equippedwith stateof the art exhaustafter-treatment syltems. In addition,more than 40 percentof the carsare over 12 yearsold, and oflhese, mosthave engines in needof major repairs. The degreeto which the existingvehicles are in needof maintenance 'voluntaqr" is reflectedby thJ resultsof the I/M programrun by the DF during 19g6through l9gg. of the over 600,000vehicles tested (209,63g in 19g6,313,720 in 19g7hd 90,405in the first four monthsof 1988), abouti}% failed the petrol vehiclestandards and g5% failed the dieselstandards (65 HSU). 146 Case studies of cities around the world Althoughthere are not as manybuses as cars,tley are considereda major pollutionsource because of the high levelsof fine particlasproduced by their dieselengines and the wide public exposureto theseemissions. On a per capitabasis, there are about16 peopleper qu in Mexico, muchmore th"q ir the highly industrializedworld and evenmore than in Brazil, for example, wherethe figure is 13. This illustratesthat thereis still a tremendouspotential for vehiculargrowth, aboveand beyond the projectedgrowth in the overall population. Not surprisingly,with sucha large andgrowing vehicle population, and with such limited pollutioncontrol of thesevehicles, Mexico City hasemerged as one of tte mostpolluted cities in the world. The problemis compoundedby stagnant meteorologicalconditions throughout the winter season,high elevation,and its physicallocation, in a bowl surroundedby mountains. The air pollutionproblem in Mexico City is probablyworse than it might otherwisebe from a public healthstandpoint because of the commutingpatterns which existthere. "More than20Vo of workersspend three or more hours commutingeach day and in ten casesdaily travel time exceedsfive hours. Some employeeslive as far as 80 km from ttreirplace of work" (Fernandez-Bremauntz and QuentinMerritt, 1991). As shownin Chapter3, commutersare amongthe segmentsof the populationmost highly exposedto motor vehicleemissions. An increasinglyintensive effort hasbeen underway to developa comprehensive packageof pollutioncontrol measures. Motor vehiclecontrols - includingmore stringentnew car standards,retrofit of someolder vehicles,and inspectionand maintenanceare important componentsof the package. New Vehicles Mexicanauthorities have decided to introducemore stringentstandards for light duty vehicles,culminating with full US autorequirements by 1993. Interim standardsfor 1989through L992ue consistentwith a proposalmade by the automobilemanufacturers. 147 Motor vehicleair pollution EmissionStandards for Mexico in g/mile HC CO Nox '89 Cars,no trucks 3.20 35.2 3.68 '90 Cars 2.88 28.8 3.20 GVW'up to 6,012lbs. (1) 3.20 35.2 3.68 GVW 6,013- 6,614lbs.(2) 4.80 56.0 5.60 '91 Cars l.t2 tl.2 2.24 GVW up to 6,012lbs.(1) 3.20 35.2 3.68 GVW 6,013- 6,614lbs.(2) 4.80 56.0 5.60 '92 Cars t.t2 tI.z 2.24 GVW up to 6,012lbs.(1) 3.20 3s.2 3.68 GVW 6,013-6,614lbs. (2) 3.20 35.2 3.68 '93 Cars 0.40 3.4 1.00 GVW up to 6,0L2lbs.(1) 3.20 35.2 3.68 GVW 6,013- 6,614lbs.(2) 3.20 3s.2 3.68 '94 Cars 0.40 3.4 1.00 GVWup ta 6,0L2lbs.(1) 1.00 14.0 2.30 GVW 6,013-6,614lbs. (2) 1.00 14.0 2.30 * GrossVehicle Weight (1) CommercialVehicles (i.e. NissanVan & Combis) (2) Light Dury Trucks when thesestandards go into full effect, Mexico will be the first Latin American country to introducecars meetingUS standards. fn-use Vehicle Retrofit Becausethe agedistribution of the vehiclepopulation contains a high percentage of old vehicles(as is typicalof manydeveloping countries), it will takemany years before new car standardscan really have a very significant effect on the environment.Any shortterm improvementsare dependenton reducingemissions from the existingfleet. Basedon the analysisby the under-secretariatof Ecology (SEDUE),strict applicationof a requirementto retrofit someof ttrevehicles (thoie capableof operatingsatisfactorily on unleadedpetrol) would havethe greatest 148 Casestudies of cities around the world pollutionreduction potential during the 1990's. They aretherefore, very interestedin pursuingthis strategy. SEDUEintends to require 1983and newer offtcial carsto be retrofittedas a first step. If this is successful,the next stepwould be to extendthe requirementto all vehiclesinvolved in transportingpeople, e.g., ta;ricabsand combis. Inspectionand Maintenance I/M is a critical elementin maximizingthe successof both new car controland in- usevehicle retrofit as well as a sourceof significantdirect emissionsreductions. Becauseit potentiallyaffects everyone who drives, it mustbe implemented carefully;for the samereason, it hasbeen the mostpolitically controversialof the "shortterm" motor vehiclestrategies under review Becauseof fearsover the public reaction,the only firm decisiontaken at ttris time wasto makeinspections of official vehiclesand those involved in transportingthe public obligatory. As a startto the scheme,Mexico City hasbuilt 8 testingstations to measure vehicleexhaust emissions and to analyzethe likely cause. As of December,1988, this systemhas been used to testrecent vintage cars (1977 through 1982model yearshave been identified as the first stagesince they areold enoughto have deterioratedsignificantly but not so old as to be impossibleto repair);the plan callsfor expansionto othervehicle groups in 1992. Fuels Over the last few years,according to PEMEX (MexicanNational Petroleum Co.), fuels improvedsignificantly in Mexico City. The lead contentof leadedfuel has beenreduced to about0.15 gramsper liter, sulfur levelsare down and a gradeof unleadedpetrol has been introduced. Further, new detergentshave been added to the petrol which are designedto reduceCO, HC and NO* emissions. Unfornrnately,no independentagency of the governmentsuch as SEDUEhas the authorityor the responsibilityto independentlyensure fuel quality. This allows and encouragesfears that evenproposed improvements in fuel quahty such as the eliminationof lead,may be donein a mannerto worsenenvironmental problems. Somehave even raised concerns that ttre introductionof unleadedfuel has increasedozone levels. Most recently,it appearsthat PEMEX hasraised the lead levelsto previouslevels. 149 Motor vehicleair pollution A Case Study of Los Angeles The Los Angeles(LA) MetropolitanArea is the populationcenter of the California SouthCoast Air Basin@asin) which constitutesa 16,600km2 area bounded by the Pacific Oceanto the west, and mountainranges to the north and east. This topographycombined with the local weatherpatterns of light winds, seabreeze, subsidenceinversions and high solar intensityproduce ideal conditionsof atmosphericstagnation conducive to pollutantreaction and buildup. The Los AngelesBasin has been one of the mostrapidly growing areasof the USA since the early 1940s. The Basinis surroundedto the eastby mountainswith a high desertarea beyontl and it hasa very low annualrainfall. Thereis sunshineall year roundand the wintersare very mild. In tre summer,a warm air capoften forms over the moist cool marineair layer which inhibitsvertical mixing. The-dominantdaily weather patternis for an on-shorebreeze to beginin the morningafter sunriseand for an off-shorebreeze to occur at night. During periodsof stagnatinghigh pressure, this circulationpattern which takespollutants out to seaat night andreturns them to land during the day allowsair pollutantsto build up in the air sheduntil the passageof a new weatherfront. The LA Basindeveloped with almostno public transportnetwork and consequentlythe residentsmust rely on the motor vehiclefor almostall transportation.The presenceof largenumbers of motor vehiclesand their intensiveconsumer oriented service activities makes the Basinthe mostpolluted areain the UnitedStates. The 8 million vehiclesin an urbanarea of 12 million peoplerepresents possibly the greatestnumber of vehiclesper person(0.67) in the world -- almosteveryone over 16 yearsold hasone! Furthermore,the areawill grow by 5 million residents,68% morevehicle-miles-travelled, and 4ovo morc trips will be takenby the year2010 (SCAG, 1989). Los Angelesair qualityhas been a major concernsince the early 1940swhen the postwiuboom brought rapid populationgrowth and industrialexpansion. since 1947,the Los AngelesAir Pollutioncontrol District (LAApcD), the precursorof the south coast Air QualityManagement District (scAeMD), beganinforcing air pollutantemission controls. Hourly ozoneconcentrations exceeding 0.6 ppm were reportedand in the 1960sozone frequently exceeded 0.5 ppm. In l96d the state of Californiabegan instituting vehicle emission sundards which werestricter than thosepromulgated later by the USEpA for the nationat large. Despitetheir strict controls,the maximumozone during the period 1986-1991only degeasedto 0.35 ppm becauseof an 81% populationincrease from 1960to 1990and allied increasesin industrialactivity andvehicular traffic. This enormouspopulation 150 Casestudies of cities around the wodd increaseresulted in manymotorists commuting 60 - 80 miles eachway to secure affordablesingle-family housing outside the centralarea. Emissionsof petrol-poweredautomobiles have been stringently controlled by the USEPAfor the past25 yearsstarting with the 1968models. Californiahas an exemptionftom the U.S. CleanAir Act that allowsit to havestricter emission standardsthan the rest of the country. The USEPAand CaliforniaAir Resources Board(CARB) standardsare shownbelow. Note how lower valueswere often implementedby Californiaseveral years before the USEPA. For example,the NO* strndardof 0.25 g/km which is to be adoptedin Californiain 1992,will be adoptedby the USEPAin 1995. Progressivetightening of petrol-poweredautomotive emissions Comparisonof USEPAand CARB EmissionStandards G/km) Year CO HC No* US CARB US CARB US CARB 1966 32 3.70 3.1 1968 ; 32 3.7 1.56 3.1 2.5 t970 24 15.6 2.r 1.56 3.1 2.5 1972 24 15.6 1.9 1.56 3.1 1.9 1973 24 15.6 1.9 1.56 1.9 1.9 t974 24 15.6 1.9 1.56 1.9 1.2 1,975 9.3 5.6 0.9 0.44 1.9 1.2 1978 9.3 5.6 0.9 0.29 r.2 0.93 1980 5.6 5.6 0.25 0.29 t.2 0.46 1983 2.1 4.4 0.25 0.29 0.6 0.46 t992 2.1 4.4 0.25 0.29 0.6 0.25 by 1995 2.1 0.16 0.25 by 2003 2.r 0.08 0.t25 Source:M. Walsh In order to meetthe Californiaand US Air Quality Standardsin the future, a three-tiered1991 Air QualityManagement Plan has been developed that will make evenmore severeemission reductions than those shown above (SCAG, 1990). This plan is basedon the September1990 CARB Low-EmissionVehicles and CleanFuels rulemaking. The major elementsof this strategyare as follows: 151 Motor vehicle air pollution a) reducinghydrocarbon a-nd NO* emlssionstandards by 80% and50% respectivelyfrom the 1990levels, b) requiringthe saleof zero-emissionvehicles starting in 1998 c) allowingthe useof vehiclespowered by alternativefuels, d) requiringavailability of suffrcientalternative fuels for thesevehicles. In addition,the plan calls for increasingthe averagevehicle ridership from the presentday 1.13to 1.5 by 1999. This will be achievedby increasingfunding for transitimprovements and high occupancyvehicle (HOU facilities,using parking feesto discouragesingle passenger commuting and providing facilities for commutingbicyclists. Alternativework weeks,telecommuting, employer rideshareincentives are alsoto be introduced. Shouldthe emissionreductions be insuffrcientto meetState and Federal air quality standardsthen contingencyactions may be necessary.These actions, including emissioncharges on petrol anddiesel fuels, vehicleuse and parking lots, user fees,time-and-place control me:nures and evenlimits on vehicleregistrations, will be quiteunpopular and may requirespecial legislation. The effectsof motor vehicleair pollutantson humanhealth have been investigated in severalstudies that haveshown significant impacts on the healthof residentsof the LA area @etelset al., 1981;Hodgkin et al., 1984;Euler et al., 1988;Abbey et al., 1990). It is estimatedthat Los Angelesresidents suffer ozone related symptoms on 17 dayseach year and an increasedmortalrty rate of 1/10,000per yearor 1600 excessdeaths from PM1s. Accordingto recentestimates, air pollutioncontrol to meetthe nationalambient air qualitystandards will cost$10 billion Slall et al., 1992). A Case Study Of Taipei The Motor VehicleProblem Vehiclesare the dominantsource of emissionsin Taipei. As recentlynoted, 'NOx, HC andCO emittedfrom motor vehiclesaccount for about50Vo of all emissions"(Shen and Huang, 1989). An especiallyimportant source, unique to Taipei is motorcycles. "Taiwanhas the highestdensity of motorcyclesin the world. Because80Vo of motorcyclesare equippedwith two-strokeengines...[they] contributeabout33% nd l0% of HC andCO emissionsrespectively. It is apparentthat to significantlyimprove the air quality in the Taiwanarea, something mustbe doneto controlvehicular pollution, especially of motorcycles(Shen and Huang,1989)." r52 Casestudies of cities around the world As a resultof rapid industrializationand motorization, Taiwan is experiencing severeenvironmental problems particularly in Taipei. The mostsevere air pollutionproblem is total suspendedparticulate. While ttrereare many contributorysourcss, the importanceof the role of the motor vehiclehas been highlightedby a recentreview of existingcoefficients ofhaze air quality data. While the area-widetrend lines are flat for the last severalyears, the problem continuesto deterioratein congestedareas. A clear correlation existsbetween the gfowth in dieselbus traffrc and the increasein the coefficient of haze. Ozoneis alsoa seriousproblem. In 1987alone, a total of 80 violationsof the air quallty standardwere notedat 4 moniloringstations. Carbonmonoxide air qualitylevels are alsoexcessive. In their analysisof the air qualityproblem in Taipei,the Taiwanesemake an especiallyperceptive observation. Because so muchof their populationis located so closeto heavilycongested areas throughout the day (eitheras a resultof their residenceor the widely prevalentuse of motor cyclesand motor bikesas a means oftravel) public exposureto high levelsof vehicleexhaust is probablygreater than in highly developedcountries. (SeeChapter 3 for a further discussionof this issue.) Efforts Underway To Solve The Problem CleanFuels Progran UnleadedPetrol - SinceAugust l, 1988,unleaded petrol of 92 octmehas been availablethroughout the entirecountry. Further, a 95 octanefuel was introduced in July 1990. LeadedPetrol - The lead contentin leadedfuel hasbeen reduced from .8 grams per liter to 0.12 since1988. MotorcycleFuel - A gradualreduction in lubricatingoil mixedwith unleaded petrol for motorcycleshas been underway since 1984. Sulfur in DieselFuel - SinceSeptember 1983, on road dieselfuel hasa maximum sulfur contentof O.5Vo. New &r Cowrols SinceJuly, 1987,all new carshave been required to complywith European standardsas containedin R 1544. StartingJuly, 1990,all new modelsand all importedcars were required to achieveuS autostandards. Domestically produced new cars must meetthe samerequirements but they are allowed waivers for up to 153 Motor vehicle air pollution threeyears. By 1994,the US standardswill applyto all new cars. While it is very diffrcult to determinethe actualsales, it is estimatedttrat about t5% of new carsmet US standardsin 1990,rising to about40Voin 1991. In an effort to acceleratethe transition,the TaiwanEPA is consideringthe introductionof a tax incentivepackage similar to the Germanand Dutch programs. Motorqcles Two levelsof controlshave been imposed on motorcycles.The first, relatively modeststage went into effectin 1988;more stringentstandards went into effect in July 1, 1991. This latter requirementwas intended to eitherrequire substantial controlor eliminationof two strokemotorcycles. The new motorcyclestandards arc 4.5 gramsper kilometerfor CO (from 8.8), and 3.0 for HC andNO* combined(from 6.5), basedon the ECE R40 testprocedure. The TaiwanEPA is consideringan additionaltightening of motorcyclestandards in 1993or 1994. In Use Controls Randomroadside inspections have been conducted by local offlrcialsfor many years. Free motorcycleand city bus emissionstests have also been encouraged. Diesels The TaiwanEPA intendsto proposethat all new dieselvehicles achieve California standardsby 1993. No dieseltaxicabs are allowedin Taipei. They are consideringa changein their regulationsto allow but not requireliquified petroleumgas (LPG) to be usedin their taxicabs. A Strategy For Progress Sincea greatdeal has been learned about reducing emissions from vehicles,one shouldnot concludethat this outcome- higheremissions and more air pollution is inevitable. Strategiesexist to both lower emissionsper kilometerdriven and reduceactual driving; applicationof both approachescan be usedto amelioratethe otherwiselikely future pollutionincreases. By way of example,an assessmentof two representativecities is presentedbelow. The potentialfor reducingemissions and improvingair quality muststart with an assessmentof existingvehicle emissions. Many factorsaffect the total inventory of motor vehicleemissions. Understanding these factors helps one to beffer structurea total inventoryof theseemissions and to determineoptimal programs for their control. Having inventoriesthat accuratelyreflect different control 154 Case studies of cities around the world measurespermit evaluationof ttre effectivenessof a given regulatoryprogram. Someof the more importantfactors follow: 1. EmissionFactors For New Vehicles- Theseemission factors can ideallybe determinedfrom the emissionstandards for new vehiclessubject to regulation or from emissiondata available for similar vehicles(e.g., similar vehicle destgn,control technologies) used in other countries. 2. Deteriorationof VehicleEmissions With VehicleAge and Mileage- Estimatinghow vehicleemissions deteriorate with time and mileageis critical in assessingin-use emissions. Different types of vehicleswith different technologies(non-catalyst petrol fueled vehicles, catalyst equipped, diesel fueled,etc.) deterioratedifferently with increasedmileage and time. This type of informationhas been determined from testingof in-usevehicles carriedout by severaldifferent countries. 3. TamperingEffects - This adjustmentaccounts for vehicleowners or drivers intentionallyaltering or disablingan emissioncontrol system. Examplesare disconnectingair pumps,catalysts, evaporative emission control systems, exhaustgas recirculating systems, and ignitiontiming. Thesevehicles are sometimestampered with in the mistakenbelief that vehicleperformance, fuel economyor other factors(e.g., maintenancetime or costs)will be improved. Informationon the effectsof tamperingwith vehicleemissions can be obtainedfrom datafrom variouscountries. However,the incidenceof vehicletampering should be estimatedfor the pafticularcountry where the inventoryis beingdeveloped. 4. VehicleMaintenance - If a vehicle(with or without emissioncontrols) is not maintainedaccording to the manufacturersrecommendations (e.g., tuneups, replacementof sparkplugs or emissioncontrol components, carburetor adjustments)the vehiclewill havesignificantly higher emissions (that is, greaterdeterioration) than one properly maintained. These higher emissions mustbe accountedfor. Someinitial estimatescan be madebased on similar informationavailable from in-usevehicle emission levels measured in other countries 5. Inspectionand Maintenanceand Anti TamperingChecks - The presenceof an effective inspectionand maintenanceprogrirm that identifieshigh emitting vehiclesand ensuresthat they are repaired(or emissioncontrol systems replaced/repairedif tamperedwith) canhelp eliminateexcess emissions resulting from the previoustwo factors. Estimatesof the benefitsof such programsis availablefrom testsconducted in differentcountries. t55 Motor vehicle air pollution 6. TechnologyMix - The proportionof vehiclesusing different technologies (e.g., diesel,non catalyst,oxidation catalyst, 3-way catalyst, etc.) is critical in estimatingtotal vehicleemissions. The proportionof technologiesused in a given country (and their appropriateemission factors) must be known or estimated. 7. VehicleAge - The numberof vehiclesof a given ageis importantto know sinceolder and/orhigher mileage vehicles usually have higher deterioration. This type of datais generallyavailable from vehicleregistration data obtained by most governments. 8. Numberof Vehicles- The total numberof vehiclesof a given modelyear in a given areais generallyobtained from vehicle registrationdata and must be known to calculatean inventory. A critical elementis to make accurate projectionsfor future years. 9. VehicleMiles TravelledPer VehiclePer Year - The numberof miles a given type of vehicletravels per yearmust be known. This numberusually varies with vehicleage with older vehiclestravelling fewer miles annually. The numberof miles travelled will be different from one country to another. 10. VehicleMisfueling - If both leadedand unleaded petrols are sold in an area where somevehicles require the use of unleadedfuel to protect ttre catalytic converter,the proportion of catalystvehicles which misfuel with leadedpetrol mustbe determined. 11. Fuel Characteristics- Fuel volatility canbe an importantdeterminant of vehicleevaporative emissions (which canaccount for as much ashalf of the total hydrocarbonemissions). Other fuel characteristicssuch as sulfur content,distillation characteristics, and oxygen content may alsobe important. 12. AmbientTemperature - The averagedaily temperature(generally maximum andminimum) must be knownto predictvehicle emissions. Generally, separateinventories are calculatedfor warm weatherconditions (when ozone levelsare at their peak)and cold weather(when carbon monoxide levels are high). Casestudic of Bangkok and Surabaya A tlryicalbreakdown of emissionsfor Bangkokand Surabayais summarizedin Figures 1 through 4. Motorcyclescan be seenas a major contributor to bottr hydrocarbonsand organic particulate and a significantsource of carbonmonoxide andlead. Dieselvehicles are the major sourceof sulfateand a significantsource 156 Casestudies of cities around the world of carbonaceousparticulate. Passengercars dominate the carbonmonoxide and leadproblems and contributesignificantly to nitrogenoxides and hydrocarbons. Different vehicle categoriestherefore, must be the focusof attentionto address different ispectsof the overallvehicle pollution problem. The major elementsof an overallvehicle pollution control strategy were summarizedeadier. In short,one must both reduceemissions per kilometer driven while simultaneouslyreducing the amountof driving. Emissionsper kilometerdriven canbe loweredby alteringsome aspects of the driving itself - averagespeed, degree of acceleration,etc. A naturaland consistenttension exists betweenaltering driving characteristicsand reducing driving sincefrequently, strategiesdesigned to increaseaverage speed by improvingtraffic flow actually enablea given roadwaynetwork to carry more vehiclesper hour and effectively increaseoverall vehicle emissions. Figures5 and 6 showthe impactof variouscontrol strategies on reducing emissionsin Bangkokand Surabaya.The first priority of courseis to restrain future vehiclegrowth. Economicmeasures, physical restrictions and selective policieswill, of course,each play a role. However,even if overall vehicle growth could be constrainedto only 5 percentper yqr, as illustratedin Figures5 and 6, vehicleemissions in Bangkokand Surabayawould explodeover the next 15 years. In additionto growth restraint,therefore, a seriesof additionalstrategies are necessary. Inspectionand Maintenance(I/M) I/M programshave been demonstrated to lower emissionsfrom existingvehicles in two ways; a) By lowering emissionsfrom vehicleswhich fail the test and are required to be repaired. b) By encouragingowners of vehiclesto takeproper care of them and to avoid the potentialcosts of repairingvehicles which havebeen tampered with or misfueled. Basedon all the dataavailable, it is estimatedthat a well run I/M programis capableof very significantemissions reductions. on the order of 25Vofor HC and CO and about10% for NO,. The lqsssignificant NO" reductionsreflect solelythe lower tamperingrates from I/M and antitamperingprograms since at presentthere hasbeen no focusedeffort to specificallydesign I/M programsto identify and correctNO, problems. r57 lll v, o z = o o o z e, o C) o z G o o o E o s ct c.i SS Nq\ G' J4 J s a0 c! o $ h ch k UJ lu bo o o o x x () o o (t) z 6 l! z O o o o 00 >| 0c t o F C) q'\ z a o r|\ u? o () bo Eti F6 a v,T, i I o sSIS ul ETIffi & J bo E f IIJ l.L L bo o 6) () q) {) O E c) o- 9 >l o z E (t E o lrl e.l ci) bo LL s s q q s G' \f LIJ tt, t o z ro x o o s @ z I E o o () E o z E o o dl G, () s u? ro ct fil k ct) tr o L trJ IIJ o oo o o c) x x o a o o z o o IIJ z a (9 o c, o lll >r E E I F IA E z o o a ar7 E Irl ci G) ka bo th ox -cG(/, oFo =v .idg F7' O T 2 E o E.e 69 l! ooEz ETIffi (t (l -o d a v, a UJ h F DO c) fil f CJ C) 6) (J F t o) o- s >\ 0q I 9 {, z o) tr a (' {, 0c o trl .+ c) a .,.bo 3000 J4 J Thousands tons per year bo E 80 q 70 6.) bo C) fil 60 .a 50 L r: () 40 o 30 (t F 20 (l a 10 c) o 0 rn Base Base l/M MC Stds O.15pb CNG CarlTruck (t) k 0.3S Buses Stds oo 600 500 400 300 200 100 o CNG Car/Truck Buses Stds (! Gt D Thousands tons per year v) 16 o Q) bo 14 c) |'.6 12 a c 10 o O 8 (J (!t a 6 F 4 RI c t 2 \o 0 (.) l/M MC Stds 0.15Pb cNG Car/Truck k, 0.3S Buses Stds b0 Motor vehicleair pollution It is alsoimportant to notethat the reductionsstart out slowly and gradually increaseover time becauseI/M programstend to lower the overall rate of fleet emissionsdeterioration. Maximum I/M benefitsare therebyachieved by adopting the programas early as possible. Stringent Motorcycle Standards Lower emissionsfrom new motorcyclesare technologically feasible. For example,in Taipei, two levelsof controlshave been imposed on motorcycles. The first, relativelymodest stage went into effectin 1988;more stringent standardswere introducedon I July 1991. The latter, will requireeither substantialcontrol, or elimination,of two-strokemotorcycles. In addition,a gradualreduction in lubricatingoil mixedwith unleadedpetrol for motorcycleshas been underway since 1984. Improved Fuel Quality Petrol Throughoutmuch of the industrializedworld, unleadedfuel hasbeen the norm for morethan a decade.Japan has actuallybeen the world leaderin this regard,with more than 90% of the petrol in that countrybeing unleaded for more than a decade. Evenwhen leadedfuel is used.the lead contentshould be reducedto no more than 0.015grams per liter. Diesel Fuel Modificationsto dieselfuel compositionhave now alsodrawn considerable attentionas a quick and cost effectivemeans of reducingemissions from existing vehicles. The two modificationswhich showthe mostpromise are a reductionin sulfur content,and in the fractionof aromatichydrocarbons in the fuel. Recently, the USEPAdecided to reducesulfur contentin dieselfuel to a maximumof 0.05 percentby weightand such fuel will soonbe introducedin WesternEurope and Japan. Sulfur Content In additionto a direct reductionin emissionsof SQ andsulfate particles, reducing the sulfur contentof dieselfuel reducesthe indirectformation of sulfateparticles 154 Casestudies of cities around the world from SO2in the atmosphere.In Los Angeles,it is estimatedthat eachpound of SO2emitted resultsin roughly one pound of fine particulatematter in the atmosphere.In this case,therefore, the indirectparticulate emissions due to SO2 from dieselvehicles are roughly as greatas their direct particulateemissions. SO2conversion to particulatematter is highly dependenton local meteorological conditions,however, so the effectscould be greateror lessin other cities. Aromatic Hydrocarbons A reduction in the aromatichydrocubon contentof diesel fuel may also help to reduceemissions, especially where fuel aromaticlevels are high. For existing dieselengines, a reductionin aromaticsfrom 35 percentto 20 percentby volume would be expectedto reducetransient particulate emissions by 10 to 15 percent and NO* emissionsby 5 to 10 percent. HC emissions,and possibly the mutagenic activity of the particulatesoluble organic fraction (SOF), would alsobe reduced. Modelling studiesof the refining industryhave shown that aromaticreductions of this magnitudecan often be obtainedthrough alterations in dieselfuel production and blending strategy,without the needfor major new investmentsin additional processingcapacity. Reduceddiesel fuel aromaticcontent would haveother environmentaland economicbenefits. The reducedaromatic content would improvethe fuel's ignition quality, improvingcold startingand idling performanceand reducing enginenoise. The reductionin the useof catalyticallycracked blending stocks shouldalso havea beneficialeffect on depositforming tendenciesin the fuel injectors,reducing maintenance costs. On the negativeside, however,the reduced aromaticsmight resultin someimpairment of cold flow properties,due to the increasedparaffin contentof the fuel. Fuel Additives A numberof well controlledstudies have demonstrated the ability of detergent additivesin dieselfuel to preventand remove injector tip deposits,thus reducing smokelevels. The reducedsmoke probably results in reducedparticulate emissionsas well, but this hasnot beendemonstrated as clearly, due to the great expenseof particulateemissions tests on in-usevehicles. Cetaneimproving additivesare alsolikely to resultin somereduction in HC andparticulate emissionsin marginalfuels. Alternative Fuels For Buses The possibilityof substitutingcleaner burning alternative firels for dieselfuel has drawn increasingattention during the last decade.The reasonsadvanced for this 165 Motor vehicle air pollution substitutioninclude conservation of oil productsand energysecurity, as well as the reductionor eliminationof particulateemissions and visible smoke. The principal alternativefuels presentlyunder consideration are naturalgas and methanolmade from naturalgas, andin limited applications,LPG. Natural Gas Naturalgas has many desirablequalities as an alternativeto dieselfuel in heavy duty vehicles. Cleanburning, cheapand abundant in manyparts of the world, it alreadyplays a significantvehicular role in a numberof countries. The major disadvantageof natural gas as a motor fuel is its gaseousform at normal temperatures. Pipelinequality naturalgas is a mixtureof severaldifferent gases but the primary constituentis metlane, which typicallymakes up 90-95percent of the total volume. Methaneis a nearly idealfuel for Otto cycle (sparkignition) engines. As a gasunder normal conditions,it mixesreadily with air in any proportion, eliminatingcold startproblems and the needfor cold startenrichment. It is flammableover a fairly wide rangeof air fuel ratios. With a researchoctane numberof 130 (the highestof any commonlyused fuel), it can be usedwith enginecompression ratios as high as 15:1(compared to 8-9:1for petrol),thus giving greaterefficiency and power output. The low leanflammability limit permitsoperation with extremelylean air fuel ratios- havingas much as 60 percentexcess air. On the other hand,its high flame temperaturetends to result in high NO* emissions,unless very leanmixtures are used. Becauseof its gaseousform andpoor self ignition qualities,methane is a poor fuel for dieselengines. Sincediesels are generally somewhat more efficientthan Otto cycle engines,natural gas enginesare likely to usesomewhat more energythan the dieselsthey replace. The high compressionratios achievable with naturalgas limit this efficiencypenalty to about10 percentof the dieselfuel consumption, however. Liquefied Petroleum Gas (LPG) Liquefiedpetroleum gas is alreadywidely usedas a vehiclefuel in the US, Canada,the Netherlands,and elsewhere.As a firel for sparkignition engines,it hasmany of the sameadvantages as naturalgas, with the additionaladvantage of being easierto carry aboardthe vehicle. Its major disadvantageis the limited supply,which would rule out any largescale conversion to LPG fuel. t6 Casestudies of cities aroundthe wodd Alcohol Fuels Methanolhas many desirable combustion and emissionscharacteristics, including goodlean combustioncharacteristics, low flametemperature (leading to low NO* emissions)zurd low photochemicalreactivity. As a liquid, methanolcan eitler be burnedin an Ono cycle engineor injectedinto the cylinderas in a diesel. With a fairly high octanenumber of ll2, and excellent leancombustion properties, methanol is a goodfuel for leanburn Otto cycle engines. Its lean combustionlimits are similarto thoseof naturalgas, while its low energydensity results in a low flametemperature compared to hydrocarbon fuels, andthus lower NO, emissions.Methanol burns with a sootlessflame and containsno heavyhydrocarbons. Methanol'shigh octanenumber results in a very low cetanenumber, so that methanolcannot be usedin a dieselengine without some supplemental ignition source. Investigationsto datehave focused on the useof ignition improving additives,spark ignition, glow plug ignition, or dual injectionwith die,selfuel. Convertedheavy duty dieselengines using each of theseapproaches have been developedand demonstrated. Emissions Methanolcombustion does not producesoot, so particulateemissions from methanolengines are limited to a smallamount of lubricatingoil. Methanol's flametemperature is alsolower thanthat for hydrocarbonfuels, resultingin NO* emissionswhich are typically 50 percentlower. CO emissionsare generally comparableto or somewhatgreater than those from a dieselengine (except for stoichiometricOtto cycle engines,for which CO emissionsmay be muchhigher). However,these emissions can be controlledwith a catalyticconverter. The major pollutionproblems with methanolengines come from emissionsof unburnedfuel andformaldehyde. Methanol (at leastin moderateamounts) is relativelyinnocuous --- it has low photochemicalreactivity, and -while acutely toxic in largedoses - displaysno significantchronic toxicity effects. Formaldehyde,the first oxidationproduct of methanol,is muchless benign, however. A powerful irritant andsuspected carcinogen, it alsodisplays very high photochemicalreactivity. While all combustionengines produce some formaldehyde,some early generationmethanol engines exhibited greatly increased emissionscompared to diesels. The potentialfor largeincreases in formaldehyde emissionswith the widespreaduse of methanolvehicles has raised considerable concernabout what would otherwisebe a very benignfuel from an environmental standpoint. t67 Motor vehicleair pollution Formaldehydeemissions can be reducedthrough changes in combustionchamber and injectionsystem design, and are alsoreadily controllable through the useof catalytic converters,at least under warmedup conditions. Recent efforts to reduce aldehydesby Detroit Dieselhave shown dramatic gains. More Stringent Car and Truck Standards Advancesin automotivetechnologies have made it possibleto dramaticallylower emissionsfrom new motorvehicles. Increasingly,countries around the world havebeen taking advantageof them. Oncegood I/M programsand unleaded petrol are introduced,state ofthe art pollutioncontrols should be pursued. Conclusions The developmentof petroleum-poweredmotor vehicleshas truly revolutionized societyover the pastcentury. The benefitsof increasedpersonal mobility and accessto goodsand servicespreviously beyond the graspof individualscannot be denied. And, yet, the relentlessgrowth in motor vehicleuse has a dark sidethat manyhave been slow to acknowledge,including a broadarray of adversepublic healthand environmentaleffects. The environmentaldamage caused by motorvehicle emissions is no longer debatable,and on a globalbasis it is increasing.The cars,trucks, and busesthat makelife better in so manyways emit morethan 800 million tons of carbonper year. From their tailpipescomes virtually all of the carbonmonoxide in the air of our cities. Less directly, they areresponsible for muchof the ozoneand smog. And motor vehiclesplay a significantrole in stratosphericozone depletion. All of thesepollutants contribute directly or indirectlyto global warming. Over the last forty years,the globalvehicle fleet hasgrown from under50 million to more than 500 million, andthere is everyindication that this growth will continue. Over the next twentyyears, the globalfleet could doubleto one billion. Unlesstransportation technology and planning are fundamentallytransformed, emissionsof greenhouseand other polluting gases from thesevehicles will continueto increase,many relatively clean environments will deteriorate,and the few areasthat havemade progress will seesome of their gainseroded. The worldwidechallenges that theseproblems pose for motor vehicle manufacturersand policy-makers are unprecedented. Nothing lessthan a revolutionin teehnologyand thinking, at leastas profoundas the initial mechanizationof transportation,is needed.Manufacturers will comeunder increasingpressure to producepetroleum-powered vehicles that are ever cleaner, safer,more reliable, andmore fuel efficient. At the sametime, they will needto 168 Case sh.rdiesof cities around the wodd developnew kinds of vehiclesthat will emit no pollutionwhatsoever. The amount of capitalneeded to accomplishthese goals will be large and, makingmatters even more diffrcult, the pressuresfor thesechanges will arisenot so muchfrom traditionalmarket forces but from public policiesadopted in responseto climate changeand other threats. While appropriatepolicies and technologies continue to develop,countries can benefitfrom the adoptionof thosethat are currentlyavailable. Varioussteps can be takento reduceair pollutionemissions from motor vehicles. Theseinclude incentivesto removeolder, higherpolluting vehicles from the road; tightening new vehicleemission standards for nitrogenoxides, volatile organiccompounds, and carbonmonoxide; developing and using cleaner fuels with lower volatility and fewer toxic components;enhancing inspection and maintenance(I&M) programs, includinginspections of anti-tamperingemission-control equipment; and extending the usefullife of pollution-controlequipment to ten yearsor 100,000miles rather than the currentfive yearsor 50,000miles. The potentialoverall impactof tighter standards,enhanced inspection and maintenance, and extendeduseful life is especiallysignificant because it helpsto ensurethat the benefitsof clean-air technologywill persistfor the full life of the vehicle. Additionalreductions in vehicularemissions can be achievedby reducing dependenceon individualcars and trucks and by makinggreater use of van and car pools, buses,trolleys, andtrains. Improvingurban traffic managementby installingsynchronized traffic lights, reducingon-street parking, switchingto "smart" roads,banning truck unloadingduring the day, and so forth can also improvetransportation system efficiency (Office of TechnologyAssessment, US Congress,1989). Providingefficient, convenient,and affiordable public transportationalternatives worldwidewould producemultiple benefis. When40 personsget out of their carsand onto a bus for a ten-miletrip to work, the emissionof some50 to 75 poundsof carboninto the air is avoided. Greateruse of public transportation would reducecongestion, cut fatalitiesand injuries from traffic accidents,and greatlyimprove air quality. 169 Motor vehicleair pollution REFEREI\CES Abbey, D.E. et al. "Inng teftn ambientconcentrations of total suspended pafticulates and oxidantsas related to incidenceof chronic diseasein California Seventh4ayAdventists" , Abstract,Second Annual Meeting of the International Societyfor EnvironmentalEpidemiology QSEE), Berkeley, CA, 13-15August (1eeo). AmericanLung Association. Thehealth costs of air pollution: a surveyof studies published1984 - 1989. (1990). Detels,R. et al. "The UCLA populationstudies of chronicobstructive respiratory disease",American Review of RespiratoryDisease, 124: 673480 (1981). Euler, G.L. et al. "Chronic obstructivepulmonary disease symptom effects of long-termcumulative exposure to ambientlevels of total oxidantsand nitrogen dioxidein CaliforniaSeventh{ay Adventist residents", Archives of Environmental Health 43: 279-285(1988). Fernandez-Bremauntz,A. and QuentinMerritt, J. Assessingthe contributionof commutingto air pollution exposurein Mexico City: a surveyof commuterhabits. @ecember1991). Hall, J.V, et al. "Valuingthe healthbenefits of cleanair", Science,225: 812-817 (reez). Hodgkin,J.E. et al. 'COPD prevalencein nonsmokersin high andlow photochemicalair pollution arqs, Chest,86:. 830-838 (1984). Hong Kong EPA. White Paper:Pollution in Hong Kong - a time to act. (5 June1989). NationalEnvironment Board of Thailand. Air and noisepollution in Thailand 1989. (1990). OECD. Transportand environment,Paris (1988). Offrceof TechnologyAssessment, US Congress.Advanced vehicle/highway systemsand urban traffic problems. Staff Paper,Science, Education, and TransportationProgram (September 1989). 170 Casestudies of cities aroundthe world Raungchat,S. Variousfactors associated with blood leadlevels of traffic policemenin BangkokMetropolis. Tbesis (undated). SCAG (SouthernCalifornia Association of Governments),Air quality management plan (draft) - SouthCoast Air Basin, South CoastAir Quality Management District, Los Angeles@ecember l99O). Shen,S-H. and Huang,K-}I. Taiwanair pollution controlprogran: impaa of and control strategiesfor transportation-inducedair pollution. Presentedat UN Conference,Ottawa, Canada (1989). World Health Organization,International Agency for Researchon Cancer,Lyon. 171, Chapter6 CASE STI]DY OF MOTOR VEIIICLE FOLLUTION AND ITS CONTROL IN GEI..IEVA FrangoisCupelin' and Olivier Zali** Traffic and Air Pollution in Geneva History and geographicalsituation Over 10,000years of historyr The first settlersin the Genevaregion were reindeer hunters who madetheir home at the foot ofthe SalEve(Figure l) over 10,000years ago. After a long period without any visible tracesof man, settlementsgrew up on tle shoresof the lake in the neolithicera. During the period of Romandomination Geneva became established as a specific entity. By the startof the Christianera, it wasno longeran outposton the fringe of the Romanworld. Thoughstill only a smalltown, it held sway over a network of farming communities,the forerunnersof mostof the villagesin the canton. As a junction for lake, road and river traffic, it rapidly developedinto a city. * FranqoisCupelin, Ph.D. chemistry,Assistant to the Chief Ecotoxicologist, ECOTOX, Geneva,Switzerland ** Olivier Zali, Ph.D. chemistry,Head, Information Unit, ECOTOX, Geneva, Switzerland I Encyclopddiede Genbve,1982 and 1984;Guichonnet, 1986 t73 Motor vehicle air pollution Frrnce GENEVA l0tm Figurel. The Cantonof Geneva,its bordersand the surroundingmountains. The fairs of the Middle Ages gaveGeneva an importantrole in Europeantrade, but the communicationroutes had remainedvirtually unchangedsince the Roman era. Following the declineof its fairs in the faceof competitionfrom Lyon in the late 15thcentury, Geneva experienced a periodof greatupheaval, which saw it changefrom an episcopalcity to the capitalof Calvinism. The Reformationalso broughta resumptionof commercialactivity. From the late 16thcentury onward Geneva became the startingpoint of many coachingroutes for mail andpassengers. Its influence,particularly in the cultural sphere,was out of proportionwith its physicalsize and its meansof communication.It was not until the early l9th centurythat theseactivities began to extendbeyond the neighboringregions. Therewere then regularcoaching servicesto Paris, Lyon, Marseille,Grenoble, Chamb6ry, Besangon, Pi6mont and the kingdomsof Italy and Naples. In 1814the Republicand Cantonof Genevajoined the SwissConfederation. 2 2 Tlre Republicand Cantonof Genevawill be referredto in this document as the Cantonof Geneva. t74 Casestudy of Geneva The strugglebetween conservatives and radicals led to the demolitionof the fortifications. This markedthe transformationfrom a pre-industrialcity to an industrialcity andushered in a periridof substantialurban expansionbetween 1850and 1880. It alsodeeply influenced the developmentof the road system:the present"inner ring" figure 2) follows the line of the old city walls. In the mid-l9th centurythe railwaysrevolutionized transport and led to the disappearanceof the coachingcompanies. ...... Nation and canton borders ( rnner and l niddle rings ' fffi$it r,ale ' Jo E Rivers U t r----=-=-==-- r.i' fr ,i.. la AJ 1a \ f14 , a o Figure 2. Tlte Genevatraffic plan is a "crown" type, with an inner ring, a middle ring and a bypassmotorway. The built up areasare shownin black. 175 Moior vehicle air pollution Genevain brief 3 The canton of Genevais locatedin a basinformed bv the mountainsof neighboringFrance @igure 1). The areaof the Canton,not includingthe Lake of Geneva,is 246 km2. The populationis concentratedin the city of Genevaand in somesurrounding conrmuneswhere new settlementshave been built, mainly in the 1960sand 1970s (Figures2 and 3). some 80% of the population(1989 data) live in an area representingless than a quarterof the Canton, and90To ofjobs are concentrated here(1985 data). 300000 250000 200000 \' -dM"a 150000 ato' 100000 soo00 o # 1850 1860 1870 1880 1910 1920 1930 1940 1950 1960 1970 1980 1990 YEAR Figure 3. Growth of the populationof the canton, the city of Genevaand the suburbanarea. Between1975 and 1985,41,000 additional jobs werecreated and 2g,000new inhabitantsarrived. The growthrate hasdecreased in more recentyears (Figure 3). 3 Servicecantonal de statistique,Genbve, various years. 176 Casestudy of Geneva In the comrnunesof the Cantonother than the city itself the proportionof commutersis over 50Voand in somecases over 80% @rimatestaet al.' 1984). Local automobiletraffrc is heavyand is supplementedby some36,000 cross-bordercommuters ('frontaliers') from the neighboringdeparfrnents of France (Ain andHaute-Savoie, see Figure 2) andsome 13,000 inhabitants of the Canton of Vaud who alsowork in Geneva(Office destransports et de la circulation, Genbve,1990). With the completionof its motorwaybypass and a sectionof motorwaynear to Morat, Genevawill be at tle centerof a motorwaynetwork comparable to that crossingthe Alps via the St. GotthardTunnel (Figure 4). TUTTGART ALLEMAGNE AUTRICHE FRANCE GRENOBLE /\tz- Figure 4. Genevalinks with the Europeanmotorway nefiilork. The land-usezoning system, of which manyare unaw.ue, aims to prqservethe rural characterof the ianton. Buildingland, includingindustrial estates and the airport, accountsfor 3lVo of the areaof the Canton,leaving almost 55% for agr:icultureand over 14% fot forests,parks and recreationalareas (FigUres 2 and 5). The possibilitiesof changingland-use zoning are strictly restricted. t77 Motor vehicle air pollution Public Agriculture, administrations, Industry,arts and diplom crafts, energy Building and civil Otherservices engineering Trade, hotel and Banking,insurancel eating, repair consultancy Transportand communications Figure 5. Different typesof land usein the canton of Geneva(service cantonal de statistique,SCS, 1991). Vegetables, toes and beets Grapes and fruit Figure6. Agriculturalproduction in thecanton of Geneva(scs, l99l). 178 Case study of Geneva Woodland and Buih-upareas and publicworks Parksand recreationalareas \-.--.------Agricultural land Figure7. Breakdownof jobs in theCanton of Genevaby the mainbranches of theeconomy (SCS, 1991). Besidescereals and vegetables, rape-seed and grapes are the major crops (Figure6). Genevais the third wine-growingCanton of Switzerland. The primarysector accounts for fewerthanT% of jobs ffigure 7). The numberof peopleworking in the secondarysector is decreasingwhile the very strongtertiary sectoris growing. The averagemonthly wage in 1989was close to 4,500Swiss francs(about US $ 3,000), which is abovethe nationalaverage. Genevais a major conference,congress and exhibition center GELECOM' motor show, etc.). Genevais alsothe homeof the EuropeanOffice of OreUnited Nations,and a numberof UN specializedagencies have their headquartershere, includingthe InternationalLabour Office (LO), the World Health Organization (WHO), the InternationalTelecommunications Union QTU), the World MeteorologicalOrganization (WMO), the World IntellectualProperty Organization (wPo), the InternationalBureau of Education0BE) andthe united NationsHigh Commissionfor Refugees(UNHCR). Thereis alsothe EuropeanCentre for NuclearResearch (CERN) and, amongthe nongovernmentalorganizations, the InternationalCommittee of the Red Cross(CRC). More than 18,000people are employedby internationalorganizations and permanent missions. t79 Motor vehicleair pollution Motor traffic and public transport Motor traffic Every year Genevahosts an impressivemotor show. with 636 motor vehiclesper thousandinhabitants, including 524 privatecars (Landry and Cupelin, 1977),the canton of Genevais also one of the mosthighly motorizedareas of the world (Figure 8). There is at presentlittle or no sign of a reversalof the upwardtrend in the numberof vehicles(Figure 9). + Total number of vehicles + P.ivate cars 65 YEAR Figure 8. Growth of the total numberof motor vehiclesand the numberof cars per 1,000inhabitants in the Cantonof Geneva(SCS, various years). The parkingproblem is acute,mainly becauseof the heavycommuter traffic. The demandsof pressuregroups for the constructionof public car parks in the city centerare becomingincreasingly insistent. up to 1989,the constructionof car parks within the inner circle wasbanned under cantonal law. Now that ttris ban hasbeen dropped, impact assessments (see section below on the air quality managementplan) are carriedout to determinewhether or not a car park canbe constructed.Swiss legislation obliges the local authorityto assessthe impacts which would result andto take all necessarysteps to ensurecompliance with the federalstandards on environmentalprotection. 180 Casestudy of Geneva 200000 150000 100000 + Private cars -*- Total numbet of vehicles s0000 0 1975 1977 1979 1981 1983 1985 1987 1989 Figure 9. Total numberof vehiclesand numberof privatecars registered in the Cantonof Geneva(SCS, various years). Figure 10. Traffic flows (numberof vehiclesper da1) at the bordersof the Canton,on the mainroutes into the city andon the bl idgesover the Rhone(SCS, variousyears and Office destransports et de la circulrtion (OTC), 1988). 181 Motor vehicle air pollution The numberof accessroutes to Geneva(Figure 10) is limited for geographical reasons,especially the presenceof the lake. The Arve andRh0ne rivers oblige drivers to usebridges on which the traffic is extremelyheavy. The Mont Blanc bridge is crossedby an averageof 90,000vehicles a day (office destransports et de la circulation,Genbve, 1990). The trafhc in the city is organizedin a "crown" systemwith an inner ring, a middle ring @igures2 and,2l) andthe future motorwaybypass of the city (see sectionon majorprojects below). Traffic enteringthe city is regulatedby an automatedsystem based on the countingof vehiclesby meansof inductioncoils. Thesefigures are permanently monitoredby a computer,which adaptsthe durationof the greenphase of traffic lights at the level of the "middlering" (Figure2). ln this way the morningqueues are kept on the outskirtsof the city so as to ensurerelatively fluid traffic flow within the city area. This rathersophisticated system cannot nevertheless regulate the traffic flow leavingthe city and cannotthen prevent an almostdaily traffic jam after office hours. Out of the 1,380,000motor vehicle journeys made every day, 78Vo are at present madeby privatecars (Office destransports et de la circulation,Genbve, 1990). For a long time, car traffrc tendedto be encouragedin the city. This led to the dismantlingof the tram networkwhich manypeople now regret. Stepshave recentlybeen undertaken to reversethis trend (seesection below on the air quality managementplan). Urban transport Geneva'sfirst tramlinewas inauguratedin 1862. The endof the last centurysaw the rapid growth of this form of transportand the changeoverfrom animaltraction to stqrm-drivenvehicles. At the beginningof this century 126km of tram lines wereelectrified @ncyclopddie de Genbve,1984). With the increasein car traffic thesetramlines were graduallytaken out of use and now there is only oneleft. on the urbanand suburban routes tle tramshave been replacedby trolley buses. The countrysideis servedby diesel{riven buses. The numberof passengerscarried bears witness to this trend (Figure l l). This graph also showsa decreasein the useof public transportfrom the late 1960s,a recoveryin the late 1970sand a sharpincrease in the late 1980s,the outcomeof a policy for developingdemand initiated by GenevaPublic Transport (rpG) with the supportof the Cantonalauthorities. 182 Ca.sestudy of Geneva 20000 1 + Trams passengels -x- Trolleybuses 100000 * Diesel buses f t- ,/ +- Total I ^,fC 80000 n r-H_*+++1 //- I + Total ll / r+rt- _-- I ,/ oa 60000 *uon 40000 20000 0 YEAR Figure 11. Trendsin the numberof passengerscarrid by the variousforms of public transportbetween 1940 and 1986. For the period 1978- 1989a revised seriesis given for the total numberof passengersusing a new methodof calculation(SCS, various years). Rail and air traffic On the 6-km stretchbetween Geneva Cornavin station and the new stationserving Genevaairport, over 200 trainsare circulatingdaily in eachdirection. This is evidenceof the qualityof the connectionswith the rer,tof Switzerland.Through the link with Bellegardeon the Frenchrail networkC eneva has a TGV (high-speedtrain) service. GenevaAirport, which handlessome 90,000 scheduled and charter flights each year, is anotherimportant component of the city's transport. Some6 million passengerswere carriedin 1990. The growth in air traffic is considerable:there were 3,700,000passengers in 1975,while projectionrfor the year2005 are for around10 million. The major projects The concernto reducetraffic within the city of Genela hasled to two major road projects:a motorwaybypassing the city and a lake crossingby bridgeor tunnel. 183 Motor vehicle air pollution Constructionof the motorwaybypass linking the Geneva-Lausannemotorway to the Frenchmotorway network started at the end of 1981and is scheduledfor completionin 1993. The plansfor a lake crossingare evenolder thanthose for the Genevabypass. They shouldbe carriedout in the foreseeablefuture, followingthe vote in 1987approving the projectin principle. The public transportnetwork is alsobeing extended,particularly with the constructionof a new tram routelinking the left andright banks. The plan to constructan automatedrapid-transit railway hasled to a controversy,and no consensushas yet beenreached. This option remainsopen. The Geneva air pollution monitoring network (ROPAG) Network of passivesamplers When the first air quality measurementnetwork was set up in 1959,emissions from heatingplants were the mainproblem. Temperatureinversion, common in the Genevabasin, was driving smokedownwards, which led, understandably,to complaintsfrom the public. The networkcomprises 18 passive samplers for sulfurdioxide. EightOwen gaugescollect the atmosphericdeposits (rains and duss) which are then analysed in the laboratory. Due to the measurestaken to limit the sulfur contentof fuels, the meanannual sulfur dioxideflow (Figure 12) hasfallen. The adventof natural gashas reinforcedthis trend. Moreover, 12 high-performanceplants operating on heavyfuel oil with a very high sulfur contenthave been or are beingconverted to alternativefuel: the heavyfuel oil is replacedby naturalgas or extra-lightoil, the sulfurcontent of whichis now limitedto 0.2 %. It mustbe addedthat the proportionof dieselpowered private cars is very low in Switzerland(less than 3%). The early days of monitoring Continuousmonitoring of air qualityby fixed measuringstations began in 1972 with the Sainte-Clotildestation @igure 13), which for yearswas an experimental pilot station. It is locatedin the city centervery closeto the ECOTOX laboratories. 184 Case study cf Ganeva mg SO2 per year 700 600 f-r.r"'""----* Garouge l 500 I -'*":__J I l_l 400 300 200 I 100 '\4 - -i-&p raa 0 60 65 70 75 80 85 90 YEAR Figure12. Trendsin the annualflux of sulfurdioxid: (SQ)measured by three passivesamplers representative of urban(ItOtel de Ville), suburban(Carouge) and rural (Landecy)environments (ECOTOX, 1991). Figure 13. Locationof the eightmeasurement stationli of the GenevaAir PollutionMonitoring Network (R OPAG). 185 Motor vehicle air pollution The stationat Anibres,which hasbeen operational since 1973 fot ozoneand was extendedin 1975.is in a rural areaon the left bankofthe lake. A van was fitted out as a laboratoryin 1978for use in the eventof accidentor disaster,but neither eventualityhas occurred. Consequentlyit wasreplaced by a laboratorymounted on a trailerin 1990. Between1976 and 1982a thoroughknowledge of the spatialdistribution of air pollutionwas acquiredby meansof circadianprofiles (Landry and Cupelin, 1977): once-a-monththe entirestaff of the departmentworked shifts for 24 hoursto take samplesat 18 measurementpoints throughout the city and canton. On the basisof the findingsthe siteswere selectedfor the fixed urbanstations of the GenevaAir PollutionMonitoring Network (ROPAG). The ROPAG network The stationswere not setup in exceptionalplaces but at pointsrepresentative of a particularenvironment. They were put into servicein turn at Meyrin (1984, suburbanenvironment fairly closeto the airport),Jussy (1985, woodland environment),Ile (1986,urban environment, heavy traffrc, town center),Wilson (1986,urban environment, heavy traffic, lakeside),Foron (1987, suburban environment,heavy traffic nearby)and finally Passeiry(1989, rural environment). The air samplesare takenon the roof of the stationat a heightof about3 meters, exceptat Jussywhere a 16-metermast is usedfbr takingmeasurements above the tree-tops. The atmosphericpollutants measured are sulfur dioxide, nitric oxide, nitrogendioxide, carbonmonoxide, ozone, total hydrocarbonsand, at four of the eight stations,methane (Figure 14). Concentrationsof pollutantsare measured continually. Every 30 minutesa half-hourlyaverage is taken. The equipmentis automaticallycalibrated every night between midnight and 12:30a.m. Mor@ver, air temperatureand humidity are continuouslyrecorded. Five stationsare equippedfor recordingwind speedand wind direction,two haveequipment for takingdust samplesand for measuringsunlight. The prevailingwinds in Genevaare the north-easterly@ise) and the south-westerly.The stationsat Anidresand Passeiry are located along the line of thesewinds as they approachGeneva, which makesit possibleto determinethe pollutionlevel of air massesapproaching and leaving the city. I-egal context Environmentalproblems have been taken into accountby Swisslegislation since the beginningof the centurywith a law on protectionof forests(1902). In 1955, a law on protectionof water cameinto force. Therewere nevertheless legislative gaps,particularly as regardsair, soii andnoise pollution. 186 Case study of Geneva ln 1971,in the midstof tle economicboom, awarene;sthat overall environmental harmonywas lacking,and that economicactivity wasproducing an exponential increasein consumptionand in waste,led the Swisspeople and the cantonsto adoptby popularvote article 24 septiesof the constitr.tion, which empowersthe Confederationto preparelegislation on environmentalprotection. The draft Law on EnvironmentalProtection (LPE) wasthe objectof wide-ranging consultationswith interestedparties. The FederalChiunbers adopted it on 7 October1983. It is a frameworklaw which is appliui throughdecrees (orders) of the FederalCouncil, ttre executiveauthority of the SrrissConfederation. Such decreesare subjectto consultationprocedures but the5'are not subjectto popular vote. Of thesedecrees, the Air ProtectionOrder (OPair),which cameinto force on 1 March 1986,sets limis to emissionsand limit valuesfor ambientair concentrations.The ambientair concentrationlimits lTable 1) aimedat protecting humans,animals and plants, their biotopesand biocoenoses, and the soil, from harmful and unpleasantair pollution. A distinctionis drawnbetween short-term limit values(daily, hourly) intendedto preventhigh concentrationsof short duration,and long-termlimit values(annual) aimed at reducingchronic exposure. The requirementto protectnot only peoplebut alsothg mostsensitive forms of life hasled Switzerlandto adoptvery high standards.Except for carbon monoxide,for whichthe24 hourslimits is not asstrirt asan 8 hoursor onehour limit, the Swissstandards are of unequalledseverity. It shouldbe notedthat these standardscorrespond, except in a f'ew details,to the limit valuesrecommended by WHO (seeChapter 2,Partl). Trends in air quality in geneva Trendsin annualmetns (ECOTOX,Geneva, 1991) Sulfurdioxide (SO) cnd carbonmonoxide (CO) The continuousmeasurements @igure 15a)confirm the trend measuredby the passivesamplers (Figure 12). The improvementin the quality of the eombustionpro;esses is at the root of the improvementin the situationfor carbonmonoxide (Fitpre 15b). The still greater improvementsince 1986 is dueto a combinationof tho adventof the catalytic convertercompulsory on new vehiclessince 15 Novenrber1986, the annual inspectionof heatingplants and the annualcompulsorl check on vehicleexhaust gases. 187 # B q) u o & c) tr a G q 9 o (DE k (^) € o € k E CI !< bo € B + (l) ! oo Case study of Geneva Substance Limit Value Statistical Definition Sulturdioxide (SO2) 30 pgtil Amual mean(arithmetic mean) )S % of half-hourly msns ovet one year 100pglm3 < 100pg/m3 X-hour avenge; should uder no circumtance 100;rglm3 )e exceededmore thm once a yar Nitrogen dioxide (NQ) 30 pgt# Annualmm (arithmetic meu) 15 % of half-hourly mams over one 100pglm3 < 100 pglm3 l4-hour average;should under no crrcum 80 pgt# re exceededmore than once a year Carbon monoxido (CO) 8 mg/n3 24-hour eversge; should under :ircumianm be exceeded more than onc Oane (O3) t8 % of half-houily mms over one monlh l0O irglrl3 < 100pglm3 r2opst# rourly rverage;should under no circumslances p exceded more lhm once e ysr (artimetic Suspendedparticulate mtterl) 70 pglm3 \nnul mean mmn) 15% of 24-hotr mm over one yar Irad (Pb) in suspended particulate matter 150pglm3 < 150 pglm3 1 pgh# Cadmium (Cd) in suspended particulate \nnusl M (arithmetic man) mtter ln no/m3 \nnul mro (arithmetic mean) Deposited particulate matter (total) 200 mglmz. dty .\nnul mru (arithmetic mean) kad (Pb) in deposited particulate lo} pgl#'day .\nnul mm (arithmetic mm) mattef . ,\nnul mm (arithmetic msn) Cadmium (Cd) in zuspended particulate 2 pgln? day mtier Znc (7a) in deposited particulale matief 4oopgl&'d^y ,\nnual mean (arithmetic mean) , \nnual mean (arithmetic mean) Thallium @) in deposited particulate 2 pglr?' d^y mattef l) Fine suspendedparticulate mtter whose termiral velocity is less tb m l0 cm/s. Notes : m8 = milligmm; I mg = 9.961 t 4g = micrcgram; I pg : 0.001 ng ng - n0ogram; I ng = 9.661 ,t < means'less thm or equal to' Table 1. Ambientair concentrationlimit values("valeurs limites d'immission") stipulatedby the Air ProtectionOrder (OPair). Motor vehicleair pollution pglm3 8O r'* 70 1 60 f-- 50 t--..---- 40+ ^ 30|.: 20 10 o --*- Ste Clotilde ---o- Meyrin Anilres Figure 15. Trendsin annualmean values for sulfur dioxide(SQ), carbon monoxide(CO), nitrogendioxide (NQ) andozone (q) at threestations representativeof urbanareas (Ste Clotilde), the suburbs(Meyrin) and rural areas (Anibres). 190 Casestudy of Geneva Nitric oxide snd. nitrogen dioxide For the nitrogenoxides Sigure 15c)there was still a ;trongupward trend until a few yearsago. The introductionofthe catalyticconv:rter triggered a decrease. The iepercussionson nitrogendioxide levels are not direct, however,since emissionmainly takesplaci in the form of nitric oxid: (NO). If a large amountof No is presentit is ttte oxidationstage that governstho No2 content. The NQ levelswitl not really fall until the amountsof NO emittedhave dropped back below a certainthreshold. Ozone(O3) Measurementof this pollutantrequires particular care on accountof its great reactivity. Figure 15dseems to showan upwardtrenC in somelocations in mean ozonelevels' we shallrefrain here from drawingan:r conclusions on this complexissue, the scopeof which extendswell beyorLdGeneva and for which the avaiiabledata need to be analysedwith caution(Land:y andCupelin, 1981). Readingstaken close to the grounddepend to a greatextent on deposition,which is goveinedby very local conditions(vegetation cover', automobile traffic' etc.). to draw conclusionsfor a generalevaluation. Measurements in the It is difficult '[he vertical dimensionare neededto confirm this trend. contributionof ECOTOX in this areatakes the form of measurementlfrom a hot-airballoon containingscientific equipment @ali andLandry, 1991). The resultsobtained so far showthat ozoneconcentrations generally rise veq' sharplywith altitudeuntil they reacha fairly constantvalue. This confirmsthat thereis a largeozone resirvoir at zrltitudeand that measurementson the gr Readingsexceeding the short-term limit values In the caseof co andSo2 the oPair limit valuesare being' or shortly will be, compliedwith (Table2). On the other hand,this is lar from beingthe casefor ozoneand nitrogendioxide. In summertimethe ozoneconcentrations very frequentlyexceed the hourly limit valuefor ambientt:oncentration. Figure 16 showsa typical exampleof the patternof concentrationson a sunnyday. It is in the countrythat the highestlevels are generallymeasured' particularly at the Jussystation whose special character has alreadybeen mentioned (measurementin the woods,above tree-top level, at :r heightof 16 meters). In 1991however, it was at the Meyrin stationin a subu::banarea that the highest hourly meanswere measuredQag y.glrf). 191 Motor vehicleair pollution 1986 \987 r988 O3 NO2 o3 N02 s()2 o3 N02 s02 ussy t9t .l0l n9e \nieres 28( 7E? 1 758 )asseiry )ynn 717 E3( t 'oton :lotllde 7t9 6g 31 1& 3t 9l 2( It t21 7a Wilson 48 JJ 2( t( r989 r990 1991 o3 N0z 03 NO2 suz o3 N02 sg2 IussY t7t9 147( t75t {ni}res ilm 7( 169 'asseiry 107! vteyrin 106: lI 62t 761 :oron I l7l 15t l. 35? 5te{lotilde 661 6i ,+0( 4t 731 31 tle l4: tn. l3: l0i Wilson 7 5( 4i 5( Table2. Numberof timesthe daily ambientconcentration limit valueswere exceededfor nitrogendioxide (NoJ, sulphurdioxide (Se) and numberof times the hourly ambientconcentration limit valuewas exceeded for ozone (or) from 1986to 1991, It shouldbe notedthat the daily ambientconcentration value for carbonmonoxide (co) was neverexceeded during this period (Ecorox, 1991) ppb 140 -x- lle 120 + AniAres + Passeiry 100 + Ste Clotilde 14 16 18 20 2i nol, Figure 16. Patternsof ozoneconcentrations for a sunnyday (July 4, l99l) at two urban stations(le and ste clotilde) andtwo rural arealtations (Anibresand Passeiry).1 ppb = 1 part per billion - 2 F,glrn3. 192 Case study of Geneva The daily limit value for ambientconcentration of nitlogen dioxide is exceededall the year round. However, the excessvalues are worse in winter when stable antiiyclonicsituations cause the Genevabasin to be c,rveredby a thick layer of stratuscloud, a signthat pronouncedtemperature invorsion is preventingthe pollutantsfrom dispersing. Besidesthe daily limit value of 80 g.g/m3stipulated b 1 the federalorder, a cantonalregulation specific to Genevaprovides for a temporaryreduction in traffic volumeif the daily meanis in excessof 160trrglm3 o.r morethan three consecutivedays @dpublique et cantonde Genlve, 1')89). In sucha case,which hasnot yet occurred,cars not fitted with a catalyticc)nverter would only be allowedon the roadsevery other day: "useof the roadsis prohibitedon even-numbereddays for motor vehicles(motor cars, inotorcycles and mopeds) with an odd-numberedregistration number, and on otld numbereddays for motor vehicleswith an even-numberedregistration number', Vehiclesfitted with a catalyticconverter are not affectedby this measure. Information Since12 March 1987a daily bulletinon air qualityhas been available on an automatictelephone answering service. This messagcis alsotransmitted by fax to the media,which may publishthe contentin wholeo: in part. The bulletincontains: - the measurementsfor the previousday in numericalform - commentson thesemeasurements antl a forecastfor the day in questionand the following day - explanationsof the mechanismswheroby the pollutantsare formed anddispersed, and adviceto peopleI rableto emit them. - a graph showingthe patternof conce,rtrationson the previousday at two tYPicalstations. A monthlysummary is alsoprepared for the mediaand for the authorities concerned.An annualreport is publishedon the meisurementsmade by the ROPAGnetwork (ECOTOX, Geneva, 1991). r93 Motor vehicleair pollution The Air Quality Management PIan as an rnstrument of Environmental Management I-egal context The strategyand principle of air potlution control The ideabehind the Federallaw is thatthe environmentbe regardedas a whole, and that the impactof differentkinds of pollution,and the correctionthereof, be dealtwith individually,collectively and in their combinedeffects. In caseswhere peopleor tle environmenthave already suffered harm, sanitationmeasures must produceresults quickly. Legislationmust reconcile the developmentof human activities,especially that of futuretechnology and the individualbehavior of consumers,with the burdenthat naturewill be ableto support. This meansthat the burdenon the environmentshould not increase,in spiteof demographicand economicgrowth. Indeed,it shouldbe reducedwherever possible. In accordancewith this principle, OPairadopts a two-prongedapproach comprisingprevention and correction. There aretherefore two phasesin the controlof emissions.In the first phase,atmospheric pollution is limited by m&Nurestaken at source. Theseare paid for by the ownerof the installation, 'polluters sinceFederal legislation recognizes the principle that pay'. However, measuresmust be technicallyfeasible and economicallybearable. Suchlimiting measuresare takenindependently of the context,and of existingsources of harm. This meansthat for the purposesof prevention,the besttechnique for reducing pollution shouldalso be usedin placeswhere ambient air concentrationsare not excessive. The secondphase implements measures to preventexcessive air pollution, increasingtle severityof normsfor emission,or reducingthe useof sourcesof pollution. where the limit valuesfor ambientair concentrationsare exceeded,the cantons mustsubmit air quality managementplans ("plans des mesures"). The deadline for implementationset by the order is I April 1994. The diffrcultiesencountered by cantonsin applyingthis new legislationhave resultedin delaysin preparingthe air quality managementplans. t94 Case studv of Geneva A few lines of action Environmentalimpact assessment(EIA) The EIA is a preventioninstrument. It allowsthe environmentalimpact of construstionor alterationof a giveninstaliation to be evaluatedin goodtime, beforeany decisionis taken. It canbe usedto ensur'i)that all the provisionsof legislationon the environmentare duly takeninto ac(ount,and it encouragesthe authorsof draftsto improvethem if necessary. An EIA shouldbe madeduring planning,and therefcre before work beginson a project. It enablesthe promoterto correctconceptual errors and revisethe investmentplan. It cantherefore also serve as an instrumentfor economic management. The EIA report is accessibleto the public, who cantrerefore judge for themselves to what extenta projectis compatiblewith environmcntalprotection. In Geneva,various EIA havealready been undertaker, including for the constructionof the motorwaybypass (I-andry et al., 1980),the alterationof the urbanwaste incineration plant @6partementdes trav;lux publics, Gen0ve, 1988) and numerousparking lot projects. Generallimitation of emissions The OPair containsa large numberof limit valuesfo: emissions,applicable to existingand future installations.Most of themare s(t for installationsof a minimum size, or for minimumvolumes of pollutantr;.For large industrial installationsand combustion plants, OPair makes a ntmberof specificprovisions. Boilersand burners over a certaincapacity are given a standardexpert evaluation prior to approvalfor sale. Emissionsfrom motor vehiclesue limitedby legislationon road trafhc. Since 1986,all vehiclesregistered in Switzerlandmust conply with the US 83 standards.Vehicles with dieselengines are the objectof new standardswhich cameinto forcein 1991. The anti-pollutionplan When it is found that an installationdoes not confornrto the requirementsof the OPair, it mustbe cleanedup. An anti-pollutionplan is preparedin collaboration with the authoritieswhich set a deadline.The usualrleadline is five years. 195 Motor vehicle air pollution Theair qualirymanagement plan when excessiveambient concentrations have been measured or are expected,the authorityestablishes an air qualitymanagement plan to preventor eliminate excessiveambient air concentration.The plan indicates: a. The sourcesof emissionsresponsible for excessiveambient air concentration,and the proportionof the total burdenof pollution for which they areresponsible; b. Measuresto preventor eliminateexcessive ambient air concentration,and an estimateof the effectivenessof eachof those measurqs. As a rule, the measureslisted in the plansare taken within five years. Air quality management plan : methodology Introduction we shall describethe methodologyapplied in Genevaduring drafting of the air quality managementplan in 1989. After consultationwith the main sectors concerned,the plan was adoptedby the conseil d'Etat of the canton of Genevaon 27 March 1991(Service de la ldgislationet despublications offlrcielles, Genbve, 1991). As part A shows,excessive air pollutantconcentrations in Genevaare causedby nitrogendioxide and ozone. In orderto keepmatters simple, we shall describe only the methodused to reducetotal nitrogenoxides (No*) emissions. ozone is a secondarypollutant produced by the joint activityof nitrogenoxides, volatile organiccompounds (voc) andsunlight. The ozoneproblem is thereforenot limited to the Genevaregion andshould be treatedon a vasterscale. As ozoneis reducedby mostprimary pollutants (CO, NO, SO2,VOC...), the air quality managementplan relatingto nitrogenoxides therefore affects ozone ambient concentration.In future years,the plan will be adaptedto ensureparallel reductionof VOC emissions. Principle of evaluation Atmosphericpollution is emittedby stationaryand mobile sources throughout the territory of Geneva. Thoseemissions are subject to the actionof wind and weather,and they are often transformedin the atmosphere. 196 Case study ofGeneva Emissionsdispersed in the atmosphereare referredto as ambientair concentrations.These are assessedby measuringthe r:oncentrationof the pollutant in questionin air samplestaken between 2 and3 metersabove ground level (see sectionabove on traffic and air pollutionin Geneva). It is assumedthat there is a causeand effectrelationship between emissions from a sourceand resultant ambient air concentration.This rreansthat the further one goesfrom a sourceof pollution,the lessnoticeable its effectswill be (Figure l7). NTRATIONS Figure 17. The relationshipbetween emissions and arnbient air concentrations. Division of tasks In Switzerland,the cantonsare responsible for checkirgthe quality of air on their territory. The resultsare assessedin the light of the ()Pair objectives. If ambient air concentrationsare excessive,the cantonalauthorit'l must prepare an air quality managementplan. This situation,described in the sectionabove on traffic and air pollution in Geneva,pertains in the cantonof Genevafor ambientair concentrationsof nitrogendioxide and ozone. 197 Motor vehicle air pollution The content of an air quality managementplan The air quality managementplan shouldname the sourcesof emissionsthat cause excessambient air concentrations,and the proportionof overall pollutionof which they are the cause. It shouldalso set out measuresfor preventionor removalof excessiveambient air concentration,and give an indicationof the effectivenessof eachof thosemeasures. Figure 18 showsthe entiremethodological procedure for implementingthe air qualitymanagement plan. MAPoF /q:17 l oF TMoDEr \ \EMtSStONS\,/ / Figure 18. Methodologyfor developmentof the air quality managementplan. 198 Casestudy of Geneva The requisite resources Model of emissions In order to meetthe objectivesof the air qualitymanigement plan, officials must map out the sourcesof emissionresponsible for excessiveemission. This calls for the useof numericalmodels, whose specifications are given in Table 3. 0uestions Sptrifications Who is producing the emissions? Qualitativeinr/entory of sources How much is emined ? Estimateof erilssions from eachsource Where are the sourcesof emission? Map of sourc(,s How will theseemissions develoo ? Evaluationof measuresset out in the plan Table3. Requisitespecifications for the numericalmrdel. Model of arnbientair concentrations The mapof ambientair concentrationsis based on tle, modelof emissions.It is essentialto ensurethat the measurestaken enable the limit valuesof ambientair concentrationto be respected.The modelis basedon the assumptionthat there is a relationshipbetween emissions and ambient air concentrations. Fluctuationof emissionsis oneof the causesof flucturtion of ambientair concentrations.Other suchfactors are changes in the meteorologicalparameters responsiblefor dilution suchas wind speedand direct on, and atmospheric stability. In order to take thesefacts into account.our modelis basedon measurements takenby the Genevanetwork for observationof atmosphericpollution (ROPAG). They havebeen correlated with dataon estimatedemir;sions around the measuring station. t99 Motor vehicle air pollution Map of emissions Sourcesof nitrogen oxide emissions The formationof nitrogenoxides results mainly from reactionbetween atmosphericoxygen and nitrogenduring combustionprocesses. A minimal proportioncomes from oxidationof nitrogencontaining compounds in the combustionmaterials themselves. With regardto emissions,we alwaystalk in termsof total nitrogenoxides (NO*). Nitrogenoxides include a largenumber of compoundsof the NnO*type, although from the point of view of air protection,the only significantonbs are NO and NOr. Nitric oxide (NO) accountsfor 90 to 95Voof NO* emissions,and it ultimatelychanges in the atmosphereinto nitrogendioxide (NOz), which is the mosttoxic. This is why NO" emissionsare expressed in termsof massof nitrogendioxide, eventhough at emissiononly 5 to l0% of NO* is nitrogendioxide. It is only that fractionthat actsas a primary pollutant. Thereare three main sourcesof emissionof total nitrogenoxides: transport, heatingand industry. Transpon In Geneva,road traffic is a majorsource of air pollution. This is explainedby the tremendousgrowth in motor traffic over the past30 years(see section above on traffic and air pollution in Geneva).It is one of the mosthighly motorizedareas in the world. Genevahas an internationalairport. Air traffic is anothersource of nitrogen oxides. For the territory of the cantonof Geneva,only emissionson the ground and during take-off and landinghave been taken into accountin the air quality managementplan. From the regionalpoint of view, only nitrogenoxides injected into the atmosphereup to a heightof 800 metersis of real importance.Emissions in the uppertroposphere may be assumedto haveno influenceon local ambient air concentrations. Heatingplant In additionto transportationand industry,NO* emissionsproduced by heating systemsare significant. 200 Case study of Geneva In this areathere are two sourcesof emissions:heati rg of homes,where emission levelsare linked to the numberof inhabitants,and he ating of workplaces,where emissionsare linked to the numberof employees,irr xpectiveof the type of activity. Emissionsproduced by heating,unlike road traffic ernissions,show considerable seasonablevariation. Whenheating emissions are comparedto traffic emissions on an annualbasis, this fact is not evident. Indastri al inst all ati ons In the cantonof Geneva,approximately 75Vo of the rrorking populationis in the tertiary sector. This is why NO, emissionsproduced by industryare relatively low. Suchemissions result from thefollowing activilies: (1) incinerationof domesticwaste, (2) industrialheating plants, (3) civil engineeringactivities, (4) agricultureand forestry. Emissionsof nitrogenoxides from industrialplantsl e,rter the atmospherethrough chimneyswhose height is calculatedto ensurethere is no excessiveambient air concentration. For civil engineering,agriculture and ibrestry, activir ies all of whichare discontinuous.emissions comes from mobilesources. It is thereforedifficult to includethem in a mapof emissions. Model of emissions Estimatingthe emissionsrequires some simplifyingl hypotheses. Appendix B describeshow this calculationhas been done. Our modeltakes account of two typesof emission. The first is emissionsfrom vehicletraffic andheating. It is mappedout in 500 by 500 squaremeter cells. Emissionsproduced by air b affic moving on tle ground in the airport, are includedin the traffic emissions.Irigure 19 showsthe sum of thesetwo sourcesof emission. 20r X td 7-r d x rn ol o f\. 'tq €< I3 -J6 \-A @ o\ \nc * on nilmm '= ffiilttr 3 t,9 oE ffix ffi5 cn5 aA rn .? cl c) m=ma x C) \n9 bo .€ tc f]*, o( o k bo Case study of Geneva The secondtype comprisesdiffuse sources of emissiior: industrialemissions evacuatedby high chimneys,and emissions from air trafftc up to 800 meters aboveground. Thoseemissions increase the generallevel of nitrogenoxides ambientair concentrationson the wholeterritory and are not linked directly to givengrid squares. Table 4 sumsup the dataon emissionof total nitrolgeltoxides. Emissions in Geneva in 1.988 (tonrslt{O1) RoadTraffic Air traffic Heatinginstallations Total Table4. Glob:rlemissions of NO* in 1988for the Cinton of Genevain tons NO*/year(ECOTOX) Map of ambient air concentrations Introduction The ideal model shouldpermit calculationof the haJf-hourlyconcentration of pollutantsand the statisticalmeans from emissiondau,, physical-chemical and photochemicalparameters of the atmosphere,and clinratic and meteorological conditions. Sucha modelcould be usedin conjuncticnwith weatherforecasts to predictconditions. At present,there are no suchrnrodels for an urbanenvironment wheresources of pollutingemissions are foundtogether. Sucha modelis yet to be designed. What we offer hereis an empiricalmodel for calculationof ambient air concentrationsbased on the hypothesisthat thereir; a linear type relationship betweenemissions and ambientair concentrations.Tlte multi-linearregression modelwill be calibratedusing data supplied by the R{)PAG networkand the estimationsmade of the emissions. 203 Motor vehicle air pollution Estimatesof future ambientair concentrationswill be expressedin averageannual concentrations.It is easyenough to incorporatethe typesof meteorological conditionsand their annualfrequency of occurrence.As alreadymentioned, emissionsfor traffic andheating are alsocalculated for annualperiods. In this way, the OPair limit valuefor ambientair concentration,which is a meanannual value, can be comparedwith the forecasts. What basic unit should be chosen? The locationsof the measuringsites are described in the sectionabove on traffic and air pollution in Geneva. Eachhas its own specialfeatures. The essential issueis that of determininghow representativethey areof the wholeterritory of Geneva. Sourcesof emissionnear the site coulddistort the ambientair concentrationpicture given by the measuringstation. In theory, the influenceof a singlesource depends on the distancebetween the sourceof emissionand the measurementsite. Experienceshows that this hypothesisis borneout for primary pollutants,such as carbonmonoxide, but that it doesnot apply to secondarypollutants resulting from physical-chemical transformations,such as ozoneand nitrogen dioxide. For the latter, we have notedthat maximumconcentration of ambientair concentrationsvaries with meteorologicalconditions and solar intensity. We havetherefore taken account of total emissionsin a grid squareof onekm2 centered on the measuringpoint. This givesa good correlationbetween emissions and ambientair concentrationsof nitrogendioxide. Model emissions/ambientair concentrations: relationshipbetween emissions and ambient air concentrationsof total nitrogen oxides In Geneva,we havefound meanmonthly concentrations of nitrogendioxide to be relativelyconstant, while, in the urbanarea, the map of emissionsshows a large proportionof NO* emissionsto be producedby heatinginstallations, even though they only work in winter. Total nitrogenoxides emissions should therefore be betterrelated to tle averageNO* ambientair concentrationsthan to average nitrogendioxide ambientair concentrations.It is shownin appendixC how this relationshiphas beenderived. Graphic representationof the map of ambient air concentrations Figure 20 showsthe map of ambientair concentrationsof nitrogendioxide for 1988,calculated from the mapof emissions.Estimations of nitrogendioxide ambientair concentrationstake accountof: 204 Case study of Geneva (1) the level per unit surfacearea of total nitrogenoxides emissions from traffic andheating installations, (2) the backgroundlevel calculatedon tho basisof estimatedforecasts thatdepend on globalemissions of tolal nitrogenoxides for the canton. The ambientair concentrationvalues thus obtainedfor eachgrid squareare then interpolatedso as to providea mapwhere nitrogen dioxide concentrationsare shownwith isometriclines. Anti-pollution measures Introduction Evaluationof total nitrogenoxide emissions showEd load traffic to be the main source. Thus the sectionof the air quality managem(nt plan devotedto sanitation measuresfor roadraffic will predominate. The renewalof the vehiclepark in Switzerlandis probablyamong the quickestin the world. It hasbeen estimated that within 13 yeiys,more than 95Vo of private vehicleswill be replaced.The progressive replacem(,nt of non-catalysedvehicles by new onesrespecting US 83 standardswill induseir strongreduction of nitrogen oxidesemissions. It will neverthelessnot be sufFtcrielttneither to reachOPair objectivesnor to resolvethe problemslinked with thc saturationof the cantonroad network. Measuresto be taken with regard to transport Guidingprinciples All the measuresset out herewere developed by the ;antonaltransport office and are describedin full in the air qualitymanagement plan of 27 March 1991. We shall mentiononly the main ones. All the measur€sllroposed meet the criteria presentedin Table5, which wereestablished with political consensus. Someof tle measuresproposed can be put into pract,ceimmediately, while others dependon completionof public works or transportbfrastructure. This meansthat they will be time tableduntil the year2000. 205 A X F C) C' 6) o4) ,oo:' d t\ U o fi h €@ *ih o\ t4 (.)0.) O k o 6 -'.?;\ rcc) x E (D ff bo ffi v o oo H o) ooooo o (o|J)!t('N o ooooo lot(9N al ct o z o ffiffiffiH8 bo It Casestudy of Geneva (a) Compliancewith Federal orders governingenvironn ental protection (b) An impact that complementsother mesuresleading to overall improvement of our environment (c) Beingrespected, and thereforehaving the supportol the population (d) Preservationof individuat liberty in termsof mobility and choice (e) Fosteringdevelopment of the viability of the city anrlcanton. Table5. Criteria for choiceof measures. Regularinformation on the air qualitymanagement plan will be distributedto the generalpublic, so that every inhabitantfeels involved, The cleaningup of road traff,rcis an ambitiousproject which doesindeed call for the supportof the population. It is all the more ambitiousin that its ains are at first sight contradictory:reduction of road traffic emissionsu'hi e maintainingor even increasingthe mobility of the population. To meetthese aims, the only alternative is to transferpart of the traffic in privatevehicles to rlther,less polluting, forms of transport. The public transportnetwork will meetttris need, and its development is a priority. Developmentof public tansport A numberof stepswill be takento improvethe pedormanceof the present network,in termsof capacity,availability, speed and comfort. It must be emphasizedthat peakhour public transportdictates the maximumavailable level. A masterplan for the public transportnetwork for thu period 1990-1994has been adopted. It entailsimprovement of existinglines, ;rrc vision of preferentialtrafflic lights at cross-roads,development of the urbannet'work with the creationof a further tramline, and reorganizationof the Genevarel;ional network. The master plan for the public transportnetwork 1995-2000airns to createa new structurefor the urbannetwork (tramsand undergroundtrains) arul to developregional transport(trains and buses). Takentogether, these measures will encouragea larg,:rproportion of journeys to be madein public ratherthan in privatetransport. 207 Motor vehicle air pollution New trffic plan The map of roadtraffic emissionsshows that the centerof town is the areawhere emissionsare highest. The high densityof emissionsleads to excessambient air concentrationsof pollutants. In orderto reducethem, city centertra{fic mustbe reduced. In order to limit traffic towardsthe center,ttre "crown" traffic systemfigure 21) is to be replacedby a systembased on sectors(Figure 22). In sucha system, passagefrom one sectorto a neighboringsector will still be possiblealong a link road, whilst passageacross two sectorswill no longerbe possiblethrough the center. Passagethrough two non-adjacentsectors will only be possibleusing a road outsidethe sectors. This new traffic systemwill maintainaccess to the center,while reducingtransit traffic. It will be introducedgradually when the bypassmotorway is openedin 1993. It shouldgradually reduce traffic in transit throughthe town by creatingsealed areas that are accessibleonly to terminal traffic. It will be extendedto tlte entireroad networkas soonas the planned bypassmotorway and road acrossthe lake are built. There could be concernthat thesearrangements will leadto a displacementof industryand housing towards the new routes,creating unexpected traffic problems. This eventualityshould be avoidedif the regulationspreventing changesin land usezoning are strictly applied. The new traffic plan objectives mustbe backedup with appropriateland-use policies. Trffic management The presenttraffic managementsystem will be modernizedand updated so as to makethe bestuse of existingand planned infrastructure. The movementof public transportvehicles in town will be a priority featureof the traffic managementsystem. A "bypass"system will be developedover 5 yearsto managethe priorities given to public transport. They will be ableto passqueues and move almostas though in a traffic-free area. Cantonalregulations will be adoptedto ensurethe coexistenceof the new form of traffrc networkwith a supplyof parkingplaces. Controlof parkingwill allow for modulationof traffic for regular,visiting andprofessional drivers. 208 Case study of Geneva Figure21. Radial/concentrictraffic plan. (Source:Cffrce des transports et de la circulation,Ddpartement de justice et police,Genbv'e. r Figure 22. Sectorbased traffic plan. (Source:Office destransports et de Ia circulation,Ddpartement de justice et police,Genbve. ) 209 Motor vehicle air pollution The establishmentof "park andride" car parksat the entry to the town will be encouraged. The building ofundergroundcar parkswill allow surfaceparking spacesto be removed,with road spacebeing redistributed for the benefitof public transport, deliveries,two-wheeled vehicles, pedestrians and greenery. Presentand plannedparking spacesfor regularcommuters will be countedand, wherepossible, reallocated to the inhabitantsof the districtsand to visitors. Measuresto be taken with regard to air traffic The canton of Genevaenjoys a Federalconcession for the use of its airport. Its powers,especially as regardspoilution, are therefore very limited. The Federalauthorities will be askedto consider,in the interestsof pollution control, limiting accessto Swissairports for certaintypes of aircraft which are deemedtoo dirty. They shouldconsider setting landing surcharges for aircraft thatcause too muchpollution. Measuresto be taken with regard to heating Striaer emissionstandards New and more binding standardsgoverning air protectioncame into force on I February1992. This shouldresult in a 40voreduction of total nitrogenoxides emissions,according to the Confederation. Reductionof energy consumption In order to reducepolluting emissionsdue to heating,energy-saving measures will be taken,with the systematicchecking of the installationof thermostats,provision of adequateregulation of domesticheating appliances, and individualbilling of heatingand hot water costs. Stepsto be taken in industry The proportionof total nitrogenoxides attributable to industryis low. Furthermore,stricter limitationson emissionscame into force on 1 Februarv 1992. Tt,efupurpose is to producea reductionof the order of 43Vo, The plant for incinerationof domesticwaste from the cantonwhich is the source of a large proportionof industrialemissions, is beingextended. Emissions of 210 Case study of Geneva nitrogenoxides will increaseby 56% unlessspeciall nteasures are taken. They are evacuatedthrough a chimneyabout 100 meters hig1h, so that they affectthe level of backgroundambient air concentration. In order to limit the impact,an emissionlimit valu,ec f 80 mg/m3has been selected.This meansthat total nitrogenoxides emiiss'ons should fall from 940 tonsof NO* per yearto 150tons of NO* per year. Evaluation of anti-pollution measures Introduction AntiPollution me&suresare evaluatedin two phasers.In the first phase,the proposedmeasurqs are evaluatedin relationto emirssirns.This involvesa sectoral approachfor the variouslisted sourcesof total nitrogtn oxides. In the second phase,the proposedmodel is usedto calculatefuture ambientair concentrations. Emissionswill be reducedstep by step. Two schedu.esfor future ambientair concentrationshave been selected, one for 1994,u'hi:h is whentle OPair ends, andthe other for the year 2000,by which time all th,: proposedmeasures should havebeen carried out. Evaluation of measuresto reduceemissions Rood trffic Accordingto the Traffic and TransportOffice (OTC) the set of measuresproposed shouldreduce individual motor traffic by t5% overall,with reductionsof up to 40%in someparts of the city center,and up to 20% in somerural areas. On the other hand,the new traffic plan will leadto nlore traffic on the bypass motorwayas of 1994,and in the regionsaffected try thelake crossing,as of the year2000. With this linear reductionin roadtraffic, overall emissionscalculated on the basisof thesehypotheses should be 2496to;ns of NO* per year for 1994 and 1367tons of NO, per yearfor 2000. Thesecalculations take accountof the gradualintroduction of the catalyser,which shouldctt the emissionfactors. Heating Accordingto Confederationestimates, introduction o i the new OPair requirements in 1992will leadto a 43% cut in emissions.The rprtdictedeffect will not be fully apparentuntil the year 2000. The estimatedcharge lor that referenceyear will be 575 tonsof NO, per year. 'r11 Motor vehicle air pollution Industry For industrialsites, tle cut in emissionswill be similar to that in heating installations.As regardsthe incinerationplant of the cantonof Geneva,the oPair standardsof 1992will not be metuntil the year 2000, at which point total nitrogen oxidesemissions for the industrialsector will be 373tons of NO, per year. Figure 23 showsall the estimatesfor total nitrogenoxides emissions. Evaluation of anti-pollution measuresrelating to ambient air concentration Accordingto the proposedmodel, the backgroundlevel of nitrogendioxide will fall at the sametime as total nitrogenoxides emissions. On the basisof estimates for emissions,a backgroundlevel of 19 p.glnf of NO2 is expectedfor 1994,and 13 p.glm3of NO2, for the year2000. To this backgroundlevel, one shouldadd the proportionof nitrogendioxide produced by roadtrafflrc and heating,calculated on the basisof emissionmaps for thosesources. Figures24 and25 showthe distributionof nitrogendioxide ambient air concentrationsfor 1994and 2000. In 1994ambient air concentrationswill be considerablylower thanin 1988. However,part of the built-uparea will still be in a zonewhere the limit valueof 3Op"glfir3 is exceeded.In criticalzones, ambient air concentrationshould not, howeverexceed an annualaverage of 40 pglm3.In the year2000, nitrogen dioxideambient air concentrationsin the cantonwill be within the limit valueof 30 pglm3. 2t2 c f € 19 L q) ^>\ () ,+ z v2 rD a aasasasi3888o6oOoOo o6)@F(OD$C?NF 6) d) L) c) v2 a (E.= c) x z a 0) o v) c.) c.l o bo {L .+ o\ o\ v1 ts c) O o li 0) o bo k c) d) x d) d0 c 2ooooo €@'ort('oi o'rrl \f =Looooo c.l Nto {1 6 c) (J O k c) q) x rc o bo k e {) b0 ok oooo(' E @|r,t('(N h ll N oooo() () 6l loto$l o0 z trammEil Motor vehicle air pollution Conclusions The air quallty managementplan will permit the achievementof the objectivesof the legislationon environmentalprotection and minimise health risks for the population. It will not give instantresults and its applicationmust be rigorously supervisedfor yearsto come. Every year, a report on how the measuresare being applied will be presentedto the Grand-Conseil(ttre Cantonal parliament) and every two yearsan updatingof the estimatesfor emissionswill be made. Comparisonof currentambient concentrationswith estimatedtrends will permit reinforcementof the proposed mglsures. So far, the air quality managementplan adoptedhas only takeninto accountthe reductionof nitrogenoxides. The next stepis to dealwith the problemof volatile organiccompounds (VOC). The measureshave been analysed in termsof their effectivenessin reducingair pollution. No cost/benefitanalyses have yet beenundertaken. The plan will be successfulonly if a majorityof the populationagrees with its objectives. An infbrmationcampaign therefore, has to be plannedin parallel with the progressiveintroduction of the variousmeasures contained in the air quality managementplan. 216 Casestudy of Geneva REFERET{CES D6partementdes travaux publics, Genbve. Rappott d'impact sur I'environnement; adaptationdes installations cantonalesde traitemetntles rdsidusde Cheneviersl[l. (1988). ECOTOX. Mesurede la qualitCde l'air d GenCvet1?X). GenUve(1991). Encyclop6diede Gendve,Tome I : Iz Paysde Gendrc, Genbve(1982). Encyclop6diede Genbve,Tome 3 : La vie desaffaire s, Genbve(1984). Guichonnet,P. (Ed.) Histoire de Gen4ve.3bme &lit:on mise l jour. Privat (foulouse)/ Payot(Genbve) (1986). Landry,J.-Cl. et al. Etudeprospective de quelquesispects de I'influenced'une autoroutesur son environnement,Archives des sciences (Genbve), 33: l-87 (1e80). Landry,J.-Cl. et Cupelin,F. Mdthoded'6valuation te la qualitdde I'air I I'aide de profilscircadiens. C.R. dessdances SPHN, 12: 4748, Genbve(1977). Landry,J.-Cl. et Cupelin,F. The monitoringof c,zoneimmissions in rural and urbanareas. InternationalJournal of Environmemlaland Analytical Chemistry, 9: 169-187(1981). OFEFP. Les cahiersde I'environnementNo 55; 6missionspolluantes du trafic routierprivd de 1950e 2000. Officefddiral de la proteaion de l'environnement, desfordtset du paysage(OFEFP), 1986,suppldment (1988). OFEFP.Les cahiersde I'environnementNo 73; ccrmnent6tablir un cadastre d'dmission. OfficefCddral de la protectionde I'environnement, des forAts et du paysage (1987a). OFEFP. Les cahiersde I'environnementNo 76; dmissionspolluantes en Suisse duesl l'activitd humaine(de 1950I 2010). OfficefCl€ral de la protectionde l'environnement,des forets et du paysage(1987b). Office destransports et de la circulation,Genbve. Ptan de chargedu rCseau routier genevois1988. 217 Motor vehicle air pollution Office destransports et de la circulation,Genbve. Donntes de la basedu syst?me de circulationgenevois, (1990). Primatesta,G. et al. Paysagesgenevois. Ed. Delachauxet Nestl6, Neuch0tel-Paris( I 984). R6publiqneet cantonde Gendve. R|glement(I{ 1 1,3) relatif d la restriction temporairede la circulationmotorisde en casde pollution de l'air, (1989). Servicecantonal de statistique,Genbve. Annuaires statistiques du cantonde Genlve, (1990,1988, 1987, 1985 et 1973). Servicede la ldgislationet despublications officielles, Genbve. Assainissementde l'air d Genive,plan de mesuresau Eensde I'article 3l de I'OPair. (27 mus 1991). Williams,M.L. The role of motorvehicles in air pollutionintheUK. The Scienceof the TotalEnvironment, 93: 1-8 (1990). Zali, O. et Landry,J.-Cl. La probldmatiquede I'ozone.Annals of Dermatology and Venereology,ll8: 917-923(1991). 218 Chapter7 SUMMARY AND CONCLUSIONS 1. The mostubiquitous air pollutionin the world todayis causedby motor vehicles. All metropolitanareas of the wodd, which containsrrme 50% of the earth's population,have or soonwill havemotor vehicle trafic congestionproblems that leadto major air pollution problemsfor the generalpublic. Although more seriousair pollution canbe producedlocally by industrialemissions and regionally/seasonallyby high sulfur contentfossil furd (coaland oil) combustion, the large and growing numberof motorvehicles pro luces continuous and extensiveair pollution. 2. Motor vehicletraffic and its emissionsseriousllg damage the healthof urban populations. Ozone,formed by complexphotochemical reactions of NO* and HC, causeseye irritation, contributesto pulmonaryirritation, provol:es asthmatic attacks in susceptibleindividuals and the developmentof chronicobstructive lung diseasein repeatedlyexposed populations. Lead (Pb) is a perniciouscomponent of particulatematter and createsa severeneurological Lealth hazard, especially for childrenliving nearhigh traffic streets. The constihents of particulatematter, eitheras emittedor as aerosolsformed by atmosphelicphotochemical reactions, causepulmonary irritation and contributeto respirafirryillness. Urban carbon monoxide(CO) affectspeople with cardiacdeficiencies and is almostentirely producedby vehiculartraffic. Nitrogendioxide (JN(l) causesatrnospheric discolorationand is a respiratoryirritant. Motor rrelLiclenoise creates a constant disturbanceto urbanlife. 3. Studiescarried out in developedcountries have dt,monstrated that fixed site air monitorsadequately characterize tle exposureofthe generalpopulation to urban air pollution. However,special studies show that th,)semonitors substantially underestimateexposures for significantsegments of the populationin closer proximity to motor vehicleemissions. It hasbeen incontrovertibly established that ambient(outdoor) air quality measured at fixed monitoringstations designed to represent,cornmunity exposures in general' significantlyunderestimates the exposuresto primaq motor vehicle air pollutants 219 Motor vehicleair pollution (Pb, CO, particlesand HC) of manypopulation subgroups. People in vehiclesin heavytraffic, peoplewalking/working along busy streetsand people whose homes front onto busy streetsare all exposedto both noiseand air pollutantsat much higher concentrationsthan reportedby the communitymonitoring networks. Thesehigh exposureshave been the subjectof specialstudies of short durationin only a few locations. 4. Availabledata indicates that exposuresin citiesto high pollutionlevels may be greaterin developingthan in industrializedcountries because ofhigher vehicle emissionrates and lifestyleswhich placepeople in closeproximity to roadways. More informationis neededon tle exposuresto automotiveair pollutantsof both the public in generaland high contactpopulation subgroups. From the few exposurestudies undertaken recently in citieswith little or no motor vehicleemission controls in place(Mexico D.F. and Manila), evidenceshows that drivers, commutersand streetsidegroups are exposedto extremelyhigh levelsof CO, Pb andparticles. There is, currently,little reliabledata on community exposuresbut there is an urgentneed now, for citiessuch as these,to initiate monitoringcampaigns to establishthe magnitudeof the problem. 5. The datanecessary to assessthe magnitudeof vehicularemissions in developing countriesare generallylacking. The magnitudemay be grosslyunderestimated if assessmentsare basedon emissionfactors that applyto testconditions in developedcountries. Althoughemission factors are establishedin standardizedconditions, actual emissionsfrom in-usevehicles are significantlyincreased by age,poor maintenanceand wear-and-tear.Computations of total vehicularemissions rely on an estimateof the mix of vehiclesby type, age,number, speed and the daily kilometersdriven. This informationis combinedwith emissionfactors (g/km) by categoryto derivethe daily emissions.Whereas the first set of dataare usually obtainable.ernission factors are calculatedand mustbe basedon datafrom other areas. Caremust be usedin applyingthese data, being sure to accountand correctfor local vehiclecharacter, fuel compositionand driving patterns. 6. Emissioncontrols by direct engineering(hardware) modifications are currently available. Existingtechnology can limit the g/km emissionrate. This canbe achieved throughintroducing changes in enginedesign, mandatory inspection and maintenance,and the use of catalyticconverters to reducethe pollutantsemitted. Fuel compositioncan alsobe adjustedto reduceemissions. These represent direct coststo the vehicleuser. 220 Summary and conclusions 7. Changesin humanbehavior and traffic patternsare necessaryto reducethe volumeof vehiculartraffic and thereby,to reduceem ssions. Indirectcontrols on drivers, suchas encouragingcarr l)ools, increasing fuel and vehicleprices, limiting urbanparking, and providirrg ow fare masstransit, can reducethe numberof vehicleson the road as well zs rheir daily kilometersdriven. The costsof theseindirect controlsare diffrcult to qutntiry. 8. Somedeveloped countries have made significant reluctions in vehicular emissions. Countriessuch as Switzerland,Japan and the USA hare successfullyintroduced direct and indirectcontrols on vehicleemissions so thrt further air quality deteriorationhas not occurred,and in most caseshas improvedsignificantly. Had theseemission controls not beenimposed (as in Gerne.'a,Tokyo and Los Angeles), air quality would havedeteriorated so badlythat massivehealth costs to the public would havebeen incurred. However,a high initial capitalinvestment is required to reapthese much greater long-term benefits. 9. Vehicleemission controls require heavy investmrgnl but shouldbe seenin the perspectiveof long term cost benefitsin termsof pub,ic health. Countrieswith motor vehiclepollution problems should begin to pl[a e in emissioncontrols appropriateto their economicand socialcontext. Sophisticatedcontrol measures can be implementedin thosecountries where financialresources are available. Thosewith fewer r()sourcescan reduce emissionsprogressively by first institutingthe simplestand most cost effective controls,such as inspectionand maintenanceprograms and use of cleanerfuels. This shouldbe followedby a phasedreduction of emi;sionsby more costly mqsures which meetpublic healthneeds and are alTordable. 10. Leastdeveloped countries should plan now to pro/ent motor vehicleair pollutionproblems from occurringin the future wh,onsignificant development startsto occur. In the next century,as the world populationincreases and economic development accelerates,the per capitanumber of vehiclesin usei,r newly developingcountries will increaseat a staggeringrate. Unlesscontrol mea;ures are appliedto reduce the useof vehicles.many growing urbanareas will experiencethe sameproblems as largecities suchas Bangkok,Mexico City or Los l\ngeles. Urban plannersand environmentalagencies should cooperate today andplm for future transportation mix with designsfor masstransit, phased emission co.rtrols, and inspectionand maintenanceprograms, that couldprevent the problens from becoming unmanageable. 221 Motor vehicle air pollution I l. Throughthe sharingof informationand experience, on a worldwidebasis, countrieswill be ableto choosemotor vehicle emission control programs which bestfit their needs. By examiningthe history of motorvehicle air pollutioncontrol in both developed and developingcountries, it will be possibleto a) evaluatethe successand failure patternsof the variousdirect andindirect control procedures that havebeen attempted,and b) choosetle controloption sequence that is appropriatefor the specificcase. Casestudies of the citiesof Bangkok,Geneva, Los Angeles, Manila, Mexico City, Surabayaand Taipei provide useful examples of the complexinteractions that are involvedin solvingair pollutionproblems. 222 Appendix A Methodology for Estimationof Numbt:rs of PeopleExposed Separatemethods were usedto estimatetle numbersof pmple exposedinside vehiclesand alongroadsides. In-Vehicles In-vehicleexposure to air pollutantsfrom motor vehiclesis a functionof several factors:(1) the averagespeed, volume and composition of traffic which varies accordingto the route andtime of travel; (2) the morleof travel andthe ventilation of the vehicle; and (3) how long the trip takes. Thesefactors are expectedto vary greatlyamong countries in waysthat havenot beentroroughly and systematically studiedand comparedfor the world's urbanpopulati,ln. For simplicity, it was assumedthat the actualnumber of peopleexposed to motor vehicleair pollutants insidevehicles is primarily a functionof how freglerrtly a personuses a motor vehicleto maketrips, i.e., personalmobility. Studiesby Zahavi(1976\ suggested that personalrnobility could be estimatedas a functionof a country'sdegree of motorization.To estimate personal mobility in urbanareas, a country'sper capitagross national product (GNP) wasused as a surrogatefor its degreeof motorizationfor two reasons.First, GNP dataare more prevalentthan motorizationdata. Second,a c(,untry'sper capitaGNP and degreJof mot<_rrizationwere found to behighly corrrilated (r = 0.887,p < 0.001) for a conveniencesample of 23 countries. This samesample of 23 countrieswas then augmentrd with mobility datafor selectedmetropolitan areas in thesecountries (Iab,le 1). It was assumedthat the mobility of eachmetropolitan area was representativ:of the mobility for all cities in the countrycontaining that metropolitanarea. ,A :egressionanalysis of these dataenabled development of the following model: Yir = 1.033295+ 0'00Cr0(6(xir) ttl where: Yir urbanvehicular triips per day per personof countryi in the 19t8(s;and Xir GNPper capitaof'country i in 1988U.S. dollars. 223 Motor vehicleair pollution Table1. Daily VehicularTrip RatesPer Personand per Capita GNp for SelectedMetropolitan Areas Worldwide. Vehicular Country's Economic trips per day per capitaGNP Group MetropolitanArea per person-a (1988US $)-g Low Income Bombay,India 0.82 340 Jakarta,Indonesia 0.77 440 Karachi,Pakistan 1.76 350 Lagos,Nigeria 0.30 290 Lower-Middle Abidjan, Ivory Coast 1.0s 770 Income Bangkok,Thailand t.l2 1,000 Bogota,Colombia t.r4 I,lg0 Cairo, Egypt 0.67 660 Mexico City, Mexico t.73 1,7& SaoPaulo, Brazil r.52 2,|ffi Upper-MiddleBuenosAires, Argentina |.37 2,520 Income Caracas,Venezuela t.25 3,250 Pusan,South Korea t.24 3,600 Seoul,South Korea 1.82 3,600 High Income Hong Kong 1.47 9,220 Munich, Germany 2.31-b 18,480 Osaka-Kobe-Kyoto,Japan 2.30-c 21,020 Paris, France 1.84-d 16,090 Sampleof British towns 1.96-e 12,810 Sampleof Frenchtowns 2.14-e 16,090 S:unpleof Spanishtowns l.l2-e 7,74fr Singapore 1.41 9,070 USA average 2.68-f 19,840 Notes: a/ Dimitriou, 1990,p 57, exceptas indicated. b/ OECD, 1988,pp. 97,100. c/ OECD, 1988,pp. 145,147. d/ OECD, 1988,p. 161. e/ Websteret al., 1985,p.22. f/ CharlesRiver Associates,1988, p. B-3. g/ World Bank, 1990,pp. 178-179. 224 Appendices This moclelwas statisticallysignificant (F = 39'313,J < 0.001)for (1' 21) degreesof freedom. The predictivepower (P = 0.65) of this modelwas respectable.This modelwas then used to estimatepetsonal mobility by vehicles in urban areasof countriesthroughout the world. Studiesby Zahavi (1976)also suggested that a crudenrodal split estimate(i.e., percentoi urban trips by automobileversus public/prarilransit) could alsobe made basedon the extentof motorizationin a particularcrou trY. Preliminarydata analysissuggested that per capitaGNP wasalso a goo1 predictorof modalsplit' but that it was not as powerfula predictoras a countrr''slevel of motorization. Consequently,the following two modelswere developcd for this purposebased on datafrom a conveniencesample of 40 citiesworldwid': (Iable 2): Yiz : 22-034+ 0.001884(Xil) I2l Y;z 18.825+ 0.097837(Xiz) t3t where: Yiz percentageof urbantrips by arrtomobileof countryi for the early1980s; Xir GNPper capitaof countryi in 1988U.S. dollars;and x;z carsper 1000population of countryi for the 1980s. The percentageof total vehiculartrips by public andJaratransit for eachcountry (Y,r) *^ computedby subtractingthe percentageof I ehiculartrips by automobile Gtt from 100 percent. For thesevariables, data firr eachcountry were available for different yearsthroughout the 1980s. Datawofie r,ot readily availablefor the sameyear for thesethree variables. 225 ^a qQr 4)l >,'=Z-rQOOo AOoOaaOOOooOOFBKS=€38=FeeR oo Efi'enss$S- l,/ =l Se l. Cl i-:i I d:(\C.l: (\ICA dP -l 991 o! € :-{l 6.) .=z x 6 () I o tr >r€l in S \nh\O (ae{ci\O (\l - d Q - (\.l -. - E€ E RI-. rn(\ - N - r- - oi \o6o\ {- c- (\l Y () Ea5:l a €[;.s.:l ool (J o'l o -l O r!.) c) (t) L< ,9 &.4 floo cqF- r^ ctr v ci ln * r r.. \o \o o\ * cl :f, \r| o\ z e's coVc.t(\tH-cA- -c.tcid E::t FSol (-) ;) L b C) '; ,ar gl Fs KI &.4 fl o cn ca \o o € i r- ct = eq .! F s! r: op a !^\ i p :q - t i+ rn rn \n \o in co \o t/1i4 \n \o $ t .t co d h \n E F 8l EE=I Q ()1.. '-E € .- (' FTE -,t -Ea- B> $ N Lr E? il?tqfl*flFurs:e$BggsE g€ u-?qe g, o. aa He E3gi+'ffiFFs *E E +(l) E.s a6 dO =v (J -Hl () \Jt i ot o '=t o ol Ht q o El= ol bo k 6* ,; xE .15 r.{ !t) a'F FEo; (g =- H? o O, nH l< d.6 c) ^.() A ;de (u o c) ;9 C) 'i,tro'Fo V) o k }e 30'F A gEs z Eg k,. r C) E8 E H(!O l-r c) 9E ts tsq, € p 8E g qQ 5 O:Y r) ;3 .g d ?Q N = Equation[2] wasstatistically significant (F 37-2,p < 0.001)for (1, 38) degreesof freedomand Equation[3] wasstatistically significant (F = 68.3, p < 0.001)for (1, 38) degreesof freedom. The predictivepower (f = 0.a9) of Equation[2] was inferior to that (f = 0.6a) of Equation[3]. Thus, Equation[2] wasused to estinatemodal splits for 21 (mositysmall) countriesfor which dataon motorizalliolwere not availableand Equation[3] was substitutedfor 138countries for whir:hmotorization data were available. The assumptionwas made that thesemodlellr, although based on a sampleof 4{t world cities, couldbe usedto estimatemodal splits for the entire urbanpopulation of other countries. Roadside For purposesof estimatinghow manypeople are expo;edalong roadsides in developingcountries, street vendors and hawkers wer€ assumedto be membersof the informal subsectorof a country'seconomy. Acr:otdingto Friedmannand Sullivan(1975), this sectorincludes handicraft worlt:er; (seamstresses, basket and mat makers,rope makers,silversmiths) street traders imd serviceworkers (peddlers,food vendors),casual construction workers (carpenters, bricklayers' plumbers,electricians), and "underground"occupatiolS (prostitutes, professional beggars,police spies,dope peddlers, pickpockets). Fl iedmannand Sullivanstated ttratttre informal sectorprovides employment for between25 and 40 percentof the urban economyin developingcountries. That percentageof the informalsector that "works lhe streets"in developing countriesand thus is exposedto motorvehicle air p'ollirtion could not be found in the literature. Thus,this studyassumed that 15 to il5 percentof the urban labor force representedan upper limit of the roadsidepopulttion for developing countries. For developedcountries, 5 to 10 percento i the urban labor force was assumedto work in roadsidesettings for lack of infrrnnationon this subject. The following equationwas usedto makethese estimaters: Y;a = k(Xn)(Xir) t4l where: Yie = tle numberof peopleexposrt' to motor vehicle air pollutionin roadsidesettings of countryi in 1990; 229 Motor vehicleair pollution the proportionof the urbanlabor force working in roadsidesettings (i.e., 15to 25 percentin developing countriesand 5 to 10 percentin developedcountries); Xi: the urbanpopulation of countryi in 1990;and Xic the percentageofthe total populationof country i in the laborforce in 1988-1990. For lack of data,the assumptionwas made that the percentageof a country'stotal populationin the labor force was similarto the percentageof its urbanpopulation in the labor force. Data on the percentageof the total populationin the labor forcecame from two sources:(UNDP, 1991;and Wright, 1991). 230 Appendices REFERT,NCE'S Arrnstrong-Wright,A. Urban transitsystems: guidelines for examiningoptions. World BankTechnical Paper Number 52, Washingtort,D.C. (1986). CharlesRiver Associates,Inc. Characteristicsof urt an transportationdemand. Urban MassTransportation Administration, U.S. Delrartmentof Transportation, Washington,D.C. (1988). Dimitriou, H. Transportand third world city develolrment.Transport Planning for Third World Cities,H. Dimitriou, d., RoutledgeLondon, England, pp. 1a9 (leeo). Hoffrnan,M., ed. The WorldAlmanac and Book of .vacts. PharosBooks, New York, New York, (1991). Organizationfor EconomicCo-operation and Develolrment. Cities and tansport, OECD,Paris, France, (1988). UnitedNations Development Programme. Human development report, Oxford UniversityPress, New York, New York, (1991). Webster,F. et al. Changingpatterns of urbantravel. EuropeanConference of Ministersof Transport,Paris, France, (1985). World Bank. WorldDevelopment Report 19X). Oxfird UniversityPress, Oxford, England,(1990). Wright, J., ed. The UniversalAlmanac 1992. An&uwsand McMeel, New York, pp. 345-476(199 1). Zahavi, Y . Trayel characteristicsin cities of devell,opingand developedcountries. World BankStaffWorking Pap'er No. 230,Washirrgon, D.C., (1976). 231 APPEh{DIX B Geneva : estimation of NO* emissions Estimation of emissionsfrom road transport Estimationof annualemissions of total nitrogenoxides from roadtraffic entails knowledgeof the parametersdefined in Table 1. The precisionof the overall estimatetherefore depends on the accuracywith which theseparameters are quantified. It wasnecessary to establishsimpli$ing hypothesesfor eachof them. Parameter Definition 1. Volumeof traffic Vehicleflow, daily distribution 2. Type of vehicle Privatecars, delivery vehicles,lorries, buses, motor-cycles,mopeds 3. Vehiclespeed Dependingon type of road and observanceof speedlimits 4. Emissioncoefficient Type of driving, mechanicalstate of vehicle, yearof manufacture Table 1. Parametersfor estimationof total nitrogenoxides emissions from road traffic. 232 Appendices Yolume of road traffrc The volumeof road traffic is calculatedwith referenrceto the traffic plan for the Genevanetwork, publishedby the office of roadtraffi,: andtransportation (OTC) in 1988(Ofrice des transports et de la circulation,Gienbve, 1988). The traffic plan showstle averagetraffic on a workinil day for the entireroad network. The map of emissionswas made to coincidewith the boundariesof the cantons. The basicgrids squaresare of 0.25 km2;the r side is therefore500 m in length. The volume of traffic is expressedin termsof vehicles/kmper day. Emissionsfor eachgrid squarewere calculated by addingtogether tle outputs from the volumeof traffic for the lengthof road. The traffic plan from the transportoffice is designulprimarily for traffic management,not for evaluationof emissions.It doesrot includeroads where the traffic flow is lessthan 1000vehicles per day. In ordt,rto gain a better ideaof emissionsdue to traffic, we evaluatedthe "sporadic"t'affic, which is not accountedfor by the OTC traffic plan. Traffic wasre.;istered manually by survey on about10 grid squares. It turnedout thatthe trafilicplan coveredan averageof 84% of all traffrc. The emissionshave been increased to take this scatteredtraffic into account. To find annualemissions, changes in trafficat weekenlshad to be considered. Using datafrom the 18 automatictraffrc countersorr tl e Genevaroad network,the averageannual volume was estimatedto be 355 times hat of an averageworking day. Type of vehicle Roadtraffic includesvarious types of vehicle. In orde:to estimatethe proportion of emissionsattributable to eachcategory of vehicle,,u e calculatedtheir respective emissionson the basisof the numberof eachtype oll v*icle registeredin the Cantonof Geneva.Table 2 showsthe emissionsfor eirchcategory of vehicle. The categoriesof vehiclewhich emit mostnitrogen ox desare private carsand heavygoods vehicles. The mapof emissionscalculate,l on the basisof the traffic plan thereforetook accountof thesetwo categories:rlo te. For heavygoods vehicles,recorded numbers of vehicleswere used to establishthe average proportionof this type of traffic for eachzone in the crmton. It has beenfound that it variesbetween 2% and4Vo. T\e proportionof reavygoods vehicles is very important,since they emit approximately10 timel more total nitrogenoxides per km thanpassenger. 233 Motor vehicle air pollution EmissionFactor Relativeemission Category Vo Number g/vh (1) % Passengercars 79 188597 1,5 65,5 Heavygoods vehicles 5 10906 13,35 33,8 Motorcycles 7 16820 0,11 0,4 Mopeds 9 2r33r(2) 0,06 0,3 (1)For 1988,speed of 50 km/haccording to reference[17] (2) Accordingto the Genevaautomobile department, 1990. Table 2. Emissionsper categoryof vehicle in relationto total numberof vehicles in 1988. Vehicle speed Vehicleemission coefficients depend to a great extenton speed. Statistical averagingis usedsince it is impossibleto know the speedof eachvehicle at every moment. The informationon traffic by categoryof speedpublished by the FederalOffice for Environment,Forests and the Countryside(OFEFP) for the different categoriesof roads(OFEFP, 1988)provided the averagestatistical values. By "speed",we meanthe commercialspeed corresponding to the relationshipbetween a givendistance and the total time neededto travel it. It takesaccount of acceleration,deceleration, delays at crossroads,etc. Table 3 shows,for the variouscategories of road, the relativedistribution of vehiclesfor differentspeeds. Emissioncoefficients The emissioncoefficients correspond to the actualquantity of pollutinggas emitted in the courseof eachkilometer travelled G/km), which dependson enginespeed and load, or in more generalterms on the averagespeed of the vehicle. Sincethe emissioncoefficients depend on the averagespeed of the vehicle,a weighted 234 Appendices Speed Non-built-upareas Non-built-upareas BuBuilt-upareas Built-up area goods Heavygoods km/h Passengercars @C) Heavy )assengercars vehicles(IIGV) ("c) Vehicles(HGV) 10 0.1 0.1 5.8 4.1 20 1.6 1.0 19.2 t7.7 30 t.l 1.1 16.7 17.3 40 3.9 6.5 18.7 17.7 50 6.5 r0.8 20.7 2t.8 60 11.1 t4.2 1.8.7 2r.2 70 14.6 2t.7 80 1,9.4 24.2 90 19.6 20.4 00 14.2 10 7.9 20 30 Table 3. Distributionof traffic by categoryof speal i r % (OFEFP). The speed limit in built-up areasis 50 km/h; outsidebuilt-up ar*s, it is 80 km/h. emissioncoefficient was calculatedwhich takesaccourt of the distributionof traffrc by categoryof speed,for eachspeed group. In order to simplify matters, the cantonwas dividedinto two zones:built-up areas:nd non-built-upareas. OFEFPcalculated the emissioncoefficients (OFEFP, 1988). A whole rangeof parameterswas taken into account.These include t'yrpc of engineand categoryof vehicle,prescriptions on exhaustgases and the numllerand types of vehiclesthere are in Switzerland. 235 Motor vehicle air pollution The emissioncoefficients for total nitrogenoxides that we haveused to calculate road traffic emissionsare shownin Table4. The sharpdecrease of ttre coefficientsfor passengercars @C) is dueto the fact that more than95% of the swissvehicles will be equippedwith a catalysorby theyears 2000, while in 1988, it wasonlv 5%. Year PC HGV PC HGV non-built-uparea non-built-uparea built-uparea built-up area 1988 2.24 16.20 t.42 14.06 1994 0.89 t4.74 0.57 t2.'t9 2000 0.40 tt.70 0.26 10.14 Table 4. Total nitrogenoxides emission coefficients expressed in g/vehicle. km (ECOTOX/OFEFP). pQ = personalcars; HGV = heavygoods vehicles. Calculationsdue to road traffic Roadtraffic emissionswere calculatedin accordancewith the parameters describedabove, and for grid squaresof500 by 500 meters. The choiceof emissioncoefficient for eachgrid squaredepended on the zoneit was in @uilt-up or non built-up area). The proportionofheavy goodsvehicles in the different regionsof the canton,2% to 4% accordingour measurements,has been taken into account. The quantityemitted is proportionalto the volumeof traffic expressedin vehicles. km, andto the emissioncoefficient expressed in g/vehicle. km. 236 Appendices Estimation of emissions due to heating Methodology A considerableproportion of total nitrogenoxides emissions arises from useof fossil fuels for air andwater heating. Evaluationof btal nitrogenoxides emissionsis difficult, sinceit dependson the follovringparameters for each installation: (1) type of tuel, (2) fuel consumption, (3) concentrationoftotal nitrogenoxides in tte combustiongases. For each500m x 5(X)mgrid square,emissions werr: calculated using the OFEFP method(OFEFP, t987a), in accordancewith the numberof workplaces,the numberof inhabitantsand emissioncoefficients. It is assumedthat emissionsare alsoproportional to degree-daysofheating, definediai the sum ofdaily differences betweenthe temperatureof the premisesheated (20' rJ) andthe averagedaily temperature,as long as it is equalto or lessthan 1i!' C (Servicecantonal de statistique,Gendve, 1991). Emissioncoefficients for heating A distinctionwas madebetween the energyrequired lor heatinghomes and that neededfor heatingindustrial workplaces. Energy c;onsumption was divided as follows: 9O%for naturalgas and extra light oil,39l f tr wood and coal, and the remainderof 7% is electricity. This resultsin an emissioncoefficient for Geneva of 45 kg of NO. per ton of fuel. The numberof degree-daysfor 1988,the referenceyear, is 3004,and the energyfactors userl are as follows: - 8.22 megajoulesper year, per inhabitantand per degreelday, - 17.54megajoules per year, per industrialworlplace andper degree/day. The emissioncoefficients of total nitrogenoxides per inhabitantand per workplace are therefore: - 1.1 kg NO* per yearand per numberof inhalbitrnts, - 2.4 kg NO,.per year andper involvedworkpla<,e. Sensitivitytets A significancepercentage of real estateis the propertl'ofthe city of Geneva. Its heatingdepartment was therefore able to checkall its installationsin order to 237 Motor vehicleair pollution obtainthe actualemission factors. The conclusionsof that studyconfirm the theoreticalcalculations of the emissionfactors. The emissioncoefficient per inhabitantfor the buildingsof the city of Genevais 1.7 kg of NO* per year. The differencemay be explainedby the fact that mostof the buildingsbelonging to the city of Genevahouse commercial premises, whose emissions are higher. Furthermore,concentrations of nitrogenoxides measured in the combustiongases are higher thanthose used in the theoreticdcalculation. This is becausethe developmentofheating technology,to ensureenergy saving, has paradoxically led to an increasein total nitrogenoxides emissions. Estimation of emissions due to industry (EIE) Genevahas a largefactory for incinerationof domesticwaste, and an EIE was publishedin 1983because of a plannedextension (Ddpartement des travaux publics,Genbve, 1988). Total nitrogenoxides emissions for 1988are estimatedat 600 tons. Someindustrial heating plants burn heavyfuel oil. A campaignto measurethe emissionsfrom thoseplants shows that they wereresponsible for approximately 65% of the 200 tons emittedby industrialinstallations. Emissions due to industrialactivities other thanheating were estimatedusing the methodology publishedby OFEFP(OFEFP, 1987b). For the Cantonof Geneva,they are of the orderof 110tons per year. 238 Appendices REFEREI.ICES Ddpartementdes travaux publics, Genbve.Rappon d'impai sur I'environnemeft; adaptaion des installaions cantonnlesde taitemen,tdes r4sidusde CheneviersIIL (1e88). OFEFP. Les catriersde I'environnementNo 55; dmissionspolluantes du trafic routierpriv6 de 1950l 2AOO.Office fddCral de la prctectionde I'environnement, desforilts et du paysage,1986, suppldment (1988). OFEFP. Les cahiersde I'environnementNo 73; co,rnnent{tablir un cadastre d'6mission. OfficefCdfiral de la protectionde l'envin'nnement,des fordts et du paysage(1987). OFEFP. Les cahiersde I'environnementNo 76; dnnissionspolluantes en Suisse (de de la proteaion de duestr I'activit6 humaine 1950l 2010). Office"fCttiral I'environnement,des for4ts et du paysage(1987). Offrcedes transports et de la circulation,Genbve. .Plnn de chargedu r€seau routier genevois1988. Servicecantonal de statistique,Genbve. Annuaires sttttistiques du cantonde Gen/ve. (1991,1990, 1988, 1987, 1985 et 1973). Servicede la ldgislationet despublications officiell,es, Genbve. Assainissement de l'air d GenCve,plan de mesuresau sensde I'anicle:3l de l'OPair. (27 mars1991). 239 Motor vehicleair pollution APPENDIX C Geneva : relationship between emissionsand ambient air concentrations of nitrogen oxides Relationshipbetween emissions and total nitrogen oxidesambient air mean concentration The total concentrationof nitrogenoxides is the sum of nitrogendioxide and nitric oxide ambientair concentrationsmeasured at the samestation. The relationship with the emissionsis of the type: : . ,EHeating [NOx] Io * lrr Er."ffi" + 1t2 where [NO*] is the averageannual concentration of total nitrogenoxides recorded at eachmeasuring station; it is expressedin pg of No2 per m3. The measuring stationis at the centerof a I kmzgrid square, Io is the backgroundlevel of ambientair concentration(pglm3), . . . pr, y2 arc the constantsexpressed in pg year km2 / m3 . tN62 , Erruffi"@1) correspondsto total annualnitrogen oxides emissions (NO*) due to tra{fic in the I km2grid squareexpressed in tons of NO2 , EHeating-@g) correspondsto total annualnitrogen oxides emissions [NO*] due toleating in the 1 km2and expressed in tonsof NO2. The valuesof Es andEr are obtainedfrom the mapof emissionsfor 19gg. The valuesused to obtainthe relationshipby multiplelinear regressionare shown in Table1. 240 Appendices E6 E1 Station NO^ @g/m3) NO* @g/m3) (measured) (t 1r16*/year.km'z)(11qg*/year.km2) (estimated) Ile 232 90 1,36 253 Wilson 170 38 57 r31 SainteClotilde 144 36 58 t32 Meyrin 71, 8 z4 78 Foron 81 7 t2 62 Anibres t9 I 0.1 44 Jussy 29 0.1 0.1 44 Table 1. Relationshipbetween emissions of NO- andambient air concentrationof NO* (annualaverage). The relationshipobtained is the following: [NO*]= 44 + 0.28.Eu * 1.36.Er (l) The cumulatedcorrelation coefficient is 0.9085. Whenthe grid squareis reducedto 500 x 500 m, the :orrelationis not so good, so the 1 km2grid squarewas preferred. Relationship between ambient air concentratio:r of total nitrogen oxides and ambient air concentration of nitrogen dioride Total nitrogenoxides emission mainly in the form of rftric oxide, is the sourceof ambientair concentrationof nitrogendioxide by oxid:tion of nitric oxide. That oxidationprocess depends on a numberof parameterrstemperature, air pressure, presenceof ozone,concentration of nitric oxide, etc. 241 Motor vehicle air pollution It hasbeen shown (Williams, 1990)drat there is a relationshipbetween ambient air concentrationof nitrogendioxide and of nitric oxide. Theremust thereforebe a relationshipbetween ambient air concentrationof nitrogendioxide and that of total nitrogenoxides. The relationshipis of the type: lNO2l= po * trr.tNOl Q) lNol = tNo_l - [No2] with [No*] > INol > 0 and INo,.l > tNot >0(3) lNOrl = Fo * ttt .(NO,l - tNO21) . lNOzl (1 + pr) = tlo * pr .[NO*] Lto Pl lNOrl= +------.[NO*] (4) (1 + pr) (1 + pr) This relationshipis valid only underthe conditionsgiven in (3). Observationshave shown that the factorp.1 of relationship2 dependson the time of year. To put it simply, the proportionof nitrogendioxide to nitric oxide is higher during the seasonswhen tropospheric ozone is formed. The relationship (2) is howeveralways checked, and checked against annual averages. For the ROPAG network, it is assumedthat in the Cantonof Genevathe meteorologicalconditions governing formation of troposphericozone are relatively homogeneous.This hypothesishas been borne out by observation. During the summersmog, hourly ozoneconcentrations are almostidentical to thoseat stations in tle rural areas. It can be assumedthat there existsfor annualambient air concentrationsof NO" and NO* a comparablerelationship for all the measuringstations. In order to verify this supposition,the relationshipbetween annual average ambientair concentrationsfor all measuringstations in 1988was calculated.The relationshipin which concentrationsare expressdin pglm3,is as follows: lNo2l = 11 + 0.268.[No*] (corr. coeff. = 0.9857)(5) 242 Appendices Concentrationsof nitrogendioxide for 1988estimated using that relationship,are given in Table 2. Station NO^ measured NO2 mt Ile 323 6t t5 Wilson 170 f, 56 SainteClotilde 144 5: 50 Meyrin 7l 41 30 Foron 8l Jz 33 Anibres T9 1l t6 Jussy 29 2( 19 Table2. Relationshipbetween annual averages of ttotalnitrogen oxides and nitrogendioxide concentrations(pglm3) The calculationmade for the years1987 and 1989shr ws that this relationship existsalso for thoseyears, and that it is almostidentir;al. As Figure I showsfor 1988,the initial conditions(.3) are at the origin of a zonein which the relationship[NO2]/[NO*] has no meaning( NOzl> [NO,l). Consequently,the ordinateat tlre origin of the relatiorrship[NOt/tNO*], valid for all the stationsof the ROPAG network, is not significant. It is useful only for the purposesof calculation. Below 15 p.g,:lrr3,the relatiotrship(5) is no longervalid. 243 Motor vehicleair pollution NO, relm3 s.O+ \\g gt/ ,z= E:'u"-l o too 2oo No* rdm3 Figure l. Relationshipbetween nitrogen dioxide and total nitrogenoxides (expressedas NO). Source:ECOTOX/ROPAG network, annualaverages for 1988. Relationship between total nitrogen oxides emissions and ambient air concentrations of nitrogen dioxide The empiricalrelationships that havebeen established, (1) and (5), enableus to relatetotal nitrogenoxides emissions to nitrogendioxide ambientair concentrations: INO*I= 44 + 0.28'Ec * 1.36'Er (1) lNo2l = 11+ 0.268'[NO*] (s) By substituting[NO*] with (1), we obtain: lNo2I= ll + 0.268.(44 + 0.28.Ec+ 1.36.Er) lNO2l= 23 + 0.075'Ec * 0.36'Er (6) 244 Appendices The empiricalrelationship obtained shows that the rneisurednitrogen dioxide ambientair concentrationsconsist of a fixed part callel the backgroundlevel, a part which is proportionalto traffrc emissions(83Vo) and a part which is proportionalto heatingemissions (l1Vo). The backlgnrundlevel is estimated, usingrelationship (6), to be 23 pglm3for 1988. Estimation of background ambient air concent:ation level The backgroundlevel dependson the volumeof emissionsfrom the regions aroundthe Cantonof Geneva. It is assumedto containa proportionof imported nitrogendioxide, which is estimatedat 4 y.gtnf for Slritzerland,and part which is directly proportionalto total NO* emissionsfrom the r:anton. We havecalculated the level of backgroundambientl ar concentrationfor the variousanti-pollution scenarios on the assumptionthat reductionin global emissionsleads to a proportionalreduction in backg;rorndpollution @ollback model). This is a criticatstep since for 1988,the bac)rgroundlevel wx 23 p.glm3 accordingto the relationshipestablished using the empirical model,or 19 pglnf from cantonalsources and 4 ltgln-tfrom outsidethe crnton. The decreasing backgroundlevels corresponding to the anti-pollutio'nr;cenarios are calculatedon the basisthat the 1988background level, corresponrls to overall1988 emissions in the Cantonof Genevaof 6567tons of NO*. REFERENCE'S Servicede la ldgislationet despublications officielles, Genbve. Assainissementde I'air d Gendve,plan de mesuresau sensde I'article 3.1de l'OPair. (27 mars 199r). Williams,M.L. The role of motorvehicles in air prol.utionin the UK. Zfte Scienceofthe TotalEnvirownent,93: 1-8 (1990). 245