Air Pollution by Motor Traffic in Dar-Es Salaam Measurements and State of the Art Description

Air Pollution by Motor Traffic in Dar-es Salaam Measurements and state of the art description

Daniel Henricson

KFB-Meddelande 1999:8 TITEL/TITLE Air pollution by motortraffic in Dar es PUBLICERINGSDATUM/DATE PUBLISHED Salaam : measurements and state of the June 1999 art description UTGIVARE/PUBLISHER FORFATTARE/AUTHOR KFB - Swedish Transport and Daniel Henricson Communications Research Board, SERIE/SERIES Stockholm KFB-Meddelande 1999:8 KFBs DNR 1997-526 ISSN 1401-1271

REFERAT (Syfte, Metod, Resultat) Dar es Salaam var Tanzanias huvudstad fram till 1973, d& den flyttades till Dodoma. Staden ar fortfarande storst med c:a 1,6 miljoner inv&nare. Projektets syfte Sr aft mata luftfororeningar dar manniskor vistas samt utgora en grand for fortsatta studier. UtOver detta soks medel for aft reducera luftfororeningar och forbattra trafiksituationen i Dar es Salaam, med en betoning p& stadens centrala delar. D& tidigare studier av luftfororeningar i Dar es Salaam bar varit mycket forcerade eller bar anvant utrustning med otillracklig noggrannhet kan detta ses som n&got av en pilotstudie. Vid v&ra matningar studerades NO, N02, S02, 03 och VOC (kolvaten) vid tv& olika matveckor. Medeltemperatur, vindhastighet och trafikflode mattes under bdda matveckoma. Trafikflodet mattes till 12 000 fordon/dygn. Andelen accelererande/retarderande fordon samt medelhastigheten studerades ocks&. Medelhastigheten uppmattes till 20 km/h. De uppmStta vardena overstiger gransvarden n&got. NivSema ar inte alarmerande htiga, men dS antalet motorfordon snabbt okar kommer luftfororeningar snart aft utgora eft betydande problem. Det hade varit onskvart aft aven mata bly, partiklar och koldioxid, speciellt partiklar d& tidigare rapporter antyder mycket hoga vSrden. Fbr aft skapa en battre Iuftkvalitet i Dar es Salaam bbr bl.a. kollektivtrafiken forbattras samtidigt som parkeringsavgifter och bensinpris hojs. Slutligen mlste branslekvaliteten forbattras och blyffi bensin snarast inforas.

ABSTRACT (Aim, Method, Results) Dar es Salaam was the capitol of Tanzania until 1973, when it was moved to Dodoma. The city is still the largest and holds about 1,6 million inhabitants. The aim of the project is to measure air pollution from traffic close to people and set a foundation for future studies. Besides that finding ways to reduce air pollution and improve traffic situation in Dar es Salaam with an emphasis on the central city parts. Previous studies on air pollution in Dar es Salaam have all been rather rushed and mostly with old and not very precise equipment. For that reason you could say this project is like a pilot study. Measurements were made on NO, NOz, S02, 03 and VOC (hydrocarbons) during two different measuring weeks. Average temperature, wind velocity and traffic flow was measured on both weeks. Traffic flow was 12 000 vehicles/day. The percentage of accelerating/retarding vehicles and average speed was also studied. Average speed was 20 km/h. The result above show levels somewhat exceeding the guidelines. The levels can not be said to be alarmingly high, but bearing the rapid increase in the number of vehicles in mind, air pollution will soon be a major problem. It would have been preferred to also measure lead, particles and carbon monoxide, especially particles since previous reports indicates very high levels. To create a better air quality in Dar es Salaam there has to be an improvement of public transport and at the same time increased parking fees and fuel prices. Finally, fuel quality has to improve and unleaded petrol has to be introduced as soon as possible.

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Air Pollution by Motor Traffic in Dar-es Salaam Measurements and state of the art description

Daniel Henricson Preface This report is an abstract from a MSc thesis with the same name. In late 19971 spent three month in Dar es Salaam, Tanzania trying to establish air pollution levels and finding out what had previously been accomplished about air pollution. The project was a cooperation between Masatu Chiguma as part of his PhD thesis and myself representing Department of Infrastructure and Planning, Traffic and Transport Planning division at KTH, Sweden. I have long wanted to work in a developing country and the situation in Tanzania seemed challenging. Except for a few sponsors, this project is self-financed. I hope that the project continues in the hands of Masatu Chiguma. Special thanks to IVL, Masatu Chiguma, Paul Hoglund, KFB and my lovely wife Jennie.

Daniel Henricson, May 1999

2 Sammanfattning pa svenska Dar es Salaam grundades 1866 av sultanen av Zanzibar. Staden var Tanzanias huvudstad fram till 1973, da den flyttades till Dodoma. Dar es Salaam ar fortfarande storst med c:a 1,6 mil]oner invanare. Projektets syfte ar att mata luftfororeningar dar manniskor vistas samt utgdra en grund for fortsatta studier. I kapitel 2 beskrivs uppkomst, egenskaper och effekter av de vanligaste luftfororeningarna: Kvaveoxider, svaveldioxid, koloxider, ozon, kolvaten, partiklar och bly. Gransvarden for luftfororeningar bygger pa bur mycket manniskan eller naturen tal utan att ta skada. I december 1997 bolls en konferens dar en grupp experter skulle fastsla gransvarden for luftfororeningar i Tanzania. Tidigare studier av luftfororeningar bar utforts av NEMC, JICA, SDP och GEEST. I tre av fyra foregaende studier anvandes Drager-metoden. Endast SDP anvande passiva provtagare. Drager-metoden bygger pa att luft dras in genom ett rdr fyllt med en reagens, som indikerar ett varde pa fororeningshalten. Osakerheten kan vara sa hog som 50 %. Generellt sett verkar tidigare rapporter vara oerhdrt forcerade. En del av matvardena ligger utanfdr metodens matomrade. Krav pa luftfuktighet och temperatur bar inte uppfyllts. Informationen ar bristande om var luftproverna bar tagits. Totalt sett ger detta en mycketdiffus bild av vad tidigare matningar star for, med undantag av SDP-matningen. Vid vara matningar anvandes passiva provtagare for NO, NOa, S02, 03 och VOC (kolvaten) vid tva olika matveckor. Samora avenue valdes som den basta matplatsen. Det ar Dar es Salaam's storsta affarsgata med mycketfotgangare pa trottoarema och tat trafik. Medeltemperatur, vindhastighet och trafikflode mattes under bada matveckoma. Trafikflodet mattes till 12 000 fordon/dygn. Andelen accelererande/retarderande fordon samt medelhastigheten studerades ocksa. Medelhastigheten uppmattes till 20 km/h. Trafikintensitet och emissioner kan antas vara konstanta over aret. Darigenom kan vara matningar utgdra en skattning av arsmedelvardet. De uppmatta varden overstiger gransvarden nagot. Nivaerna ar inte alarmerande hoga, men da antalet motorfordon snabbt okar kommer luftfororeningar snart att utgdra ett betydande problem. Det hade varit onskvart att aven mata bly, partiklar och koldioxid, speciellt partiklar da tidigare rapporter antyder mycket hoga varden. Pa marknaden finns datormodeller for att berakna luftfororeningar. Med hjalp av dessa kan man pa ett mycket kostnadseffektivt rakna fram nivaer for CO och N02. Inga modeller ar kalibrerade for tanzanska forhallanden och det kommer sakert att kravas mycket arbete innan de kan anvandas dar. For att skapa en battre luftkvalitet i Dar es Salaam bor man bl.a. forbattra kollektivtrafiken samtidigt som parkeringsavgifter och bensinpris hojs. Slutligen maste branslekvaliteten forbattras och blyfri bensin snarast inforas.

3 Contents Contents...... 4 Abbreviations...... 6 1. Introduction...... 7 1.1 Background and history on Dar es Salaam...... 7 1.2 Purpose and aim with the project...... 7 1.3 Problem identification...... 8 1.4 Methodology...... 8. 1.5 Boundaries...... 8. 2. Description of different air pollutants...... 9 2.1 Nitrogen oxides...... 9. 2.2 Sulphur dioxide...... 9. 2.3 Carbon oxides...... 9. 2.4 Ozone...... 3. 2.5 Hydrocarbons...... 10 2.6 Particles...... 10 2.7 Lead...... 1.0 3. Air pollution standards...... 11 3.1 Standards from EU, WHO and UNECE...... 11 4. Previously performed measurements...... 13 4.1 The Drager detector tube method...... 13 Measuring spots...... 14 4.3 Resultsfrom air pollution measurements...... 15 4.4 Analysis of the results...... 1.6 5. Our measurements...... 17 5.1 Type of measuringequipment...... 17 5.2 Choice of measuring spot...... 17 5.3 Results from air pollution measurements...... 18 5.4 Results from meteorological measurements...... 18 5.5 Measurements of traffic...... 1.8 5.6 Analysis of the results...... 19 6. Computer models on traffic related air pollution...... 21 6.1 Description of Swedish and Dutch models...... 21 6.2 Possibilities of application in Tanzania...... 22

4 7. Measures to reduce air pollution in Dar es Salaam...... 23 7.1 General measures to reducetraffic...... 23 7.2 Measures to reduce emissions from traffic...... 23 7.3 Measures to reduce specific air pollutants...... 24 8. References...... 25 8.1 Books and reports...... 25 8.2 Newspapers and magazine articles...... 25 8.3 Personal interviews...... 25 Abbreviations General abbreviations AIG Avgaser i Gaturummet (Streetlevel exhaust gases) CAR Calculation of Air pollution from Road traffic GEEST Centre for Energy, Environment, Science and Technology DSM Dar es Salaam EU European Union IVL Institutet for Vatten och Luftvardsforskning (Swedish Environmental Research Institute) JICA Japan International Cooperation Agency KTH Kungliga Tekniska Hogskolan (Royal Institute of Technology) NEMC National Environment Management Council NILU Norsk Institutt for Luftforskning (Norwegian Institute for Air Research) ppb Parts per billion ppm Parts per million SDP Sustainable Dar es Salaam Project SNV Svenska Naturvardsverket (Swedish Environmental Protection Agency) UNECE United Nations Economic Commission for Europe WHO World Health Organisation

Chemical abbreviations CO Carbon monoxide C02 Carbon dioxide COHb Carboxyhaemoglobin HCOx Hydrocarbons HN03 Nitric acid ho 2 Hydoxyl ro 2 Peroxy NO Nitrogen monoxide no 2 Nitrogen dioxide NOx Nitrogen oxides o 2 Oxygen 03 Ozone Pb Lead PM10 ParticulateMatter (< 10 pm) so2 Sulphur dioxide SPM Suspended Particulate Matter VOC Volatile Organic Compound

6 1. Introduction

1.1 Background and history on Dar es Salaam

I have the honour to report the return of the Sultan after a ten clays’absence at Dhar Salaam, the proposed site ofa new townon the mainland littoral, a few hours’ steaming southof Zanzibar. The Sultan is expending large sums of money upon the transport of building material to this place, where he is at present erecting a palace, a fort and dwellings for his officials.

The above text is a report from Dr. G.E. Seward of the British Consulate in Zanzibar to The Chief Secretary to Gor, Political Department, Bombay dated Nov 10th 1866. 1866 was obviously the year when Dar es Salaam was founded, though it was then referred to as Dhar Salaam, later Darra Salaam and in 1873 called Dar-es-Salaam. The town was founded at the mouth of the river Kingani and soon became an important DAR-ES-SALAAM BY 1911.

trading port.

In 1961, Tanzania gained independence after being colonialized by Germany and later The United Kingdom. The period between 1961 and 1973 was characterised by a rapid increase in population accompanied with industrial and commercial growth. In 1973, Tanzanian government decided to move the capitol from Dar es Salaam to Dodoma, in the central parts of the country. So far, most of the national administration has remained in Dar es Salaam. In 1992 Dar es Salaam had a population of approximately 1.6 millions and an annual growth rate of about 5 %.

1.2 Purpose and aim with the project Four previous studies on air pollution measurements have been performed in Dar es Salaam, but they have all been rather rushed and mostly with old and not very precise equipment. Most of them show up to 30 min average during peak hours. The Drager equipment used in most samples is not a very objective method because it leaves a lot

7 of judging to the one performing the analysis. For that reason you could say this project is like a pilot study. The aim of the project is to measure air pollution from traffic close to people and set a foundation for future studies. Besides that finding ways to reduce air pollution and improve traffic situation in Dar es Salaam with an emphasis on the central city parts.

1.3 Problem identification The traffic volumes in Dar es Salaam are rapidly increasing. In fact, the number of imported vehicles rose from 4,300 in 1993 to 16,300 in 1994. The majority of the cars imported today are reconditioned or second-hand Japanese cars from the early eighties of which none have catalytic converters. The fuel quality is poor and unleaded petrol cannot be found in Tanzania. At present, there are no regulations on the amount of pollution allowed in motor vehicle emissions. Therefor engines are often run down and maladjusted. Within Dar es Salaam, only about 60 % of the roads are unpaved and producing a lot of dust when trafficked. There is a growing problem of air pollution in Dar es Salaam. One mustnot forget that owning a car is a great achievement and is looked upon as an important symbol of status. This shift of transport mode is a big step in the direction of becoming an industrialised nation, for good and for bad. This pilot studyand state of the art description will try to identify these problems and in some aspects suggest means for improvement. Fortunately, there seem to be trend of a greater awareness of the air pollution problem in Tanzania.

1.4 Methodology Passive samplers were used to measure air pollution. All samplers were mounted on a streetlight and a guard was hired to protect them. After a week they were taken down and sent for analysis. The procedure was repeated at the second measuring week. Some other more or less basic instruments were used to determine the height of the buildings surrounding the measuring spot, traffic flow, temperature and wind velocity. The gathering of information necessary for this project has been made on several institutions and libraries in Dar es Salaam, both from printed text and from personal interviews. A few sources of general character have been gathered in Sweden.

1.5 Boundaries This report deals with air pollution caused by motor traffic. There are of course several other sources of air pollution, but they are not described in this study. There are several other types of pollutants that are not part of this report. The emphasis is on the most important pollutants that are all accounted for in chapter 2. Geographically the boundaries are the Dar es Salaam region, with a strong emphasis on the central parts.

8 2. Description of different air pollutants

2.1 Nitrogen oxides The major sources of nitrogen oxides are volcanic action and lightning. Anthropogenic emissions come from heating, power generators and transport (combustion engines). Atmospheric nitrogen is oxidised to NO during combustion and later oxidised to NOa. Nitrogen oxides is a collective term for nitric oxide, NO and nitrogen dioxide, N02. When emitted into the air NO is quite rapidly transformed into N02. Therefore, N02 is more important for the human health. NOz is a reddish-brown gas. A varietyof respiratory problems has been associated with exposure to N02. Young children and asthmatics are at risk from ambient N02 exposure, which may result in chronic bronchitis or other respiratory diseases. Nitrogen oxides also contribute to acid deposition and vegetation effects. Plants are more sensitive to nitrogen dioxide during the growing season and especially to interactive effects with sulphur dioxide, so 2. 2.2 Sulphur dioxide The main sources of sulphur dioxide, S02 are the burning of fossil fuel, and industrial sources like smelting of ores and manufacturing of paper. The amount of S02 emitted from a motor vehicle is depending on the concentration of sulphur in the fuel. S02 is a colourless gas that can react with many airborne particles. It is soluble in water and can be oxidised within a water droplet. After having been emitted from high chimneys sulphur is eventuallyoxidised further to sulphuricacid and giving rise to acid rain. Several environmental problems are associated with acid rain, including the killing of fish and the leaking of nutrients from soil. Other effects include damage to human respiratory function, especially when exposed in combination with particles. Sulphur dioxide is also damaging to plants at moderate concentrations, especially at interactive effects with nitrogen dioxide.

2.3 Carbon oxides The major source of atmospheric carbon monoxide, CO is the spark ignition engine. If the presence of oxygen is sufficient, most CO is instantly oxidised to carbon dioxide, C02. However, this is not the case in an Otto-engine, especially under idling and decelerating conditions. Carbon monoxide, CO is a colourless, odourless, tasteless gas that is lighter than air. Effects on the human body when inhaled are that CO disrupts the supply of 02 to the body, in other words suffocation. The lowest level of which notable effects on vegetation have been observed is 115 mg/m3 .

2.4 Ozone Ground level ozone, 03 is a so-called secondary pollutant formed in atmospheric reactions involving oxides of nitrogen and hydrocarbons. Their mayor sources are motor vehicles. The oxides react in the presence of sunlight. This reaction usually gives the highest concentration of ozone some kilometres downwind from the source. Stratospheric ozone is not a pollutant but part of the ozone layer protecting the earth from ultraviolet radiation. Ozone is known to be the main source of photochemical smog.

9 There is evidence of negative health effects from human exposure to ozone. 235 jig/m3 is not to be exceeded as an hourly average more than once per year. Damage to plants may occur at much lower levels, sometimes as low as 100 pg/m3 .

2.5 Hydrocarbons Mayor sources of hydrocarbons in the air are evaporation of solvents and fuels, and the partial combustion of fuels. Partial combustion gets more common when the petrol- or diesel engine is maladjusted or improperly maintained. Hydrocarbons are not just one chemical substance but a group of pollutants where carbon and hydrogen are the common denominator. More than 200 hydrocarbon compounds have been found in ambient air samples. Both petrol and diesel contain hundreds of different hydrocarbons plus several other chemical compounds. Hydrocarbons are an essential precursor of photochemical air pollution (see section 2.4). Because of the great diversity of hydrocarbons in polluted air, it is not possible to determine its toxic levels. Some individual compounds, as benzene is cancerous, while others such as ethene is a plant growth hormone and mayaffect crops.

2.6 Particles Particles can come from industrial sources as well as vehicle traffic. Unpaved roads contribute considerably to the amount of greater particles in the air. Smaller particles can be produced in the diesel engine. Particulate matter is a mixture of organic and inorganic substances, liquids or solids. Visible particles like soot stick to the hair in nostrils and throat, while particles smaller than 1 pm can reach the inner parts of the lungs. Particles are removed from the air by both wet and dry deposition. Particles in combination with sulphur dioxide and black smoke can cause increased mortality. Short term exposure to particles without interaction with other pollutants are observed to cause increased mortality above 500 pg/m3 (smoke) and a reduction in lung function for children at 180 pg/m3 (total suspended particulates). The latest research on the area concludes that it is the very small particles that cause most harms to the human body. These particles (0.01-1 pm) are invisible to the eye but can reach the inner parts of the lungs. This cause heart- and respiratory problems and in some cases premature death. Besides these effects, exposure to particles often gives a feeling of discomfort. Another effect of particles is the soiling of buildings and other exposed.

2.7 Lead Lead is a pollutant that has been deliberately introduced into the environment as an anti-knocking petrol additive in the 1920’s. In the mid 1980’s unleaded petrol started to be sold in many European countries, but in most third world countries, leaded petrol is still the predominant type. It has been concluded that at least 90 % of the air lead in urban areas was from petrol before reduction of lead content of petrol. Lead is a heavymetal. Atoms of lead can sometimes stick to small particles and through respiration reach the inner parts of the lungs. In human beings lead affects blood circulation, reproduction, kidney and nervous system. It is likely to cause learning disabilities and hyperactivity in children. Lead can affect hearing and brain and cause gravidity complications. Many studies demonstrate lead is causing retardation in development in children. The impacts of lead in humans can be seen at the lowest blood lead levels. It is a health hazard at any level of exposure.

10 3. Air pollution standards One important mean to reach improved air quality is to implement air pollution standards. The standards are based on how much human or nature can handle without destructiveeffects. These standards could either be recommendations -guide values, or compulsory -limit values. One assumption for the implementation of air pollution standards is that one has the capability to monitor the pollution levels accurately. In December 1997, a group of experts held a convent concerning the introduction of air quality standards in Tanzania.

3.1 Standards from EU, WHO and UNECE Different authorities have issued different air pollution standards. The most widespread standards come from the European Union, World Health Organisation and United Nations Economic Commission for Europe. The standards could be expressed in different ways. For instance, the 98-percentile means that the concentration of a certain pollutant must not exceed the limit in 98 % of the time (1 hour, 1 day et.c.). The standards are usually expressed in pg/m3 but air pollution concentrations are sometimes given in ppm, which is a volume to volume ratio.

3.1.1 Standards for protection of human health Sulphur dioxide, S02 Value Specification Type Issued [ng/m 3 ] by 120 50-percentile (1 year, daily average) Limit value EU 180 50-percentile (6 winter months, daily av.) Limit value EU 350 98-percentile (1 year, daily average) Limit value 40-60 1 year daily average Guide value 100-150 Daily average Guide value 500 Maximum 10 minutes average Guide value WHO | 350 Maximum hourlyaverage Guide value 125 24-hour average Guide value | 50 Yearly average Guide value ______

Nitrogen dioxide, N02 | Value Specification Type Issued [pg/m3 ] by 200 98-percentile (1 year, hourly average) Limit value EU 135 98-percentile (1 year, hourly average) Guide value 50 50-percentile (1 year, hourly average) Guide value 200 Maximum hourlyaverage Guide value WHO 150 Maximum daily average Guide value | 40-50 Yearly average Guide value

Carbon monoxide, CO Value Specification Type Issued [pg/m3 ] by 100 Maximum 15 minutes average Guide value WHO 60 Maximum 30 minutes average Guide value 30 Maximum hourly average Guide value 10 | Maximum 8-hour average Guide value

11 Breathable particles, PM10

1 Value Specification Type I Issued I 1 tug/m3 ] by 70 Maximum 24-hour average Guide value I WHO I 150-200 Maximum hourly average Guide value WHO | 100-120 8-hour average Guide value | WHO |

Lead, Pb

I Value Specification I Type Issued I [ng/m 3 ] by 2 Yearly average I Limit value EU I I 0.5 Yearly average | Guide value WHO |

3.1.2 Standards for protection of plants Nitrogen dioxide, N02

Value Specification Type Issued I [ug/m3 ] by 95 4-hour average Guide value WHO I 30 Yearly average (NO+NO2) Guide value WHO & UNECE I

Sulphur dioxide, S02

Value Specification Type Issued by 100 Daily average Guide value WHO 30 Yearly average Guide value WHO

Ozone, 03

Value Specification Type Issued I [pg/m3 ] by I 200 Maximum hourly average Guide value WHO 65 Daily average Guide value WHO 60 Average for the crop season Guide value WHO 50 Average for the crop season Guide value UNECE 150 Hourly average Guide value UNECE 60 8-hour average Guide value UNECE |

12 4. Previously performed measurements When this project started there had been four known previous studies of air pollution in Dar es Salaam. Three out of four were made using the Drager detector tube method, Only the NILU-study used passive samplers, most likelyof the same type that was used in our measurements. The passive sampler method is described under section 5.1 below.

4.1 The Drager detector tube method The Drager equipment consists of a number of detector tubes and a bellow pump. A length-of-stain detector tube is a glass tube containing chemical reagents in which a colour change maybe produced when a sample of the atmosphere is drawn through it by the bellow pump. The length of the stain produced provides a measure of the concentration of a specified contaminant in air. Short-term detector tubes are used for measurements lasting up to 15 minutes. The relative overall uncertainty can be as much as 50 %.

13 4.2 Measuring spots

4.2.1 The NEMC study The first study was performed in 1992 by Chemistry Department at University of Dar es Salaam. It was commissioned by NEMC. They took samples of CO, SPM, Pb, N02, S02, HCOx and C02 on the following locations: Askari Monument, Kariakoo, Gerezani, MuhimbiliMedical Centre and Bahari Beach Hotel. There are no records in the report on how high above streetlevel or how far from the road the samples of air

DAR ES SALAAM

1. Askari Mon 7. Gerezani 13. Manzese AMBIENT AIR 2. Samora Av/Morogoro Rd 8. Muhimbili Medical C 14. Bureauof Stds/Ubungo MCACiiRiMrt 3. SDR office 9. Chang'ombe Road 15. Ardhi Institute V 4- Kariakoo 10. Radio Tanzania 16. DSM Airport LOCATIONS 5. Arnoutoglu 11. R Kawawa Rd 17. Oysterbay o ftamci Hennoon 6. Kivukoni ferry______12. New Kigogo Rd 18. Bahari Beach are taken.

4.2.2 The JICA study The second was performed in 1994 by JICA. The study was commissioned by Ministry of Works, Communication and Transport. The measuring of air pollution was part of an extensive investigation involving traffic surveys and road maintenance. Ambient air measurements were made on NO, N02 and CO. The survey was conducted at the following locations: Chang ’ombe Road, Rashidi Kawawa Road and New Kigogo Road. There are no records in the report on how high above streetlevel or how far from the road the samples of air are taken. Beside the measurements of ambient air, JICA also performed an automobile exhaust gas survey.

4.2.3 The SDP study The third study is part of an ongoing project supervised by SDP. The measurements were made in 1995 by NILU. NC2 and S02 were measured for one week. The ten

14 stations were situated as follows: SDP office, Amoutoglu, Kivukoni ferry, Gerezani, Radio Tanzania DSM, Manzese, Tanzania Bureau of Standards, Ardhi Institute, DSM International Airport and one control station. The samplers were placed on the rafters of roofs (about 3 m above ground) and close to the road.

4.2.4 The GEEST study The fourth was made in 1996 by GEEST. The report also contains comparative results from the first two studies. They measured CO, C02, S02, NOx, SPM and HCOx. Samples of air pollution were taken on five different locations: Samora Avenue/Morogoro Road, Kariakoo, Ubungo, DSM International Airport and Oysterbay. All pollutants were measured about 2 m above the ground. At each measurement of air pollution, temperature and wind velocity readings were made.

4.3 Results from air pollution measurements

CO [mg/m3 ] C02 [mg/m3 ] S02 [mg/m3 ] Pb Location fug/m3 ] NEMO JICA GEES NEMO GEES NEMO SDP GEES NEMC T T T Gerezani 94 8 800 3.4 <0.001 43 Kariakoo 88 6.2 8 600 5 300 3.3 0.26 76 Askari Mon 68 6 800 3.3 59 Muhimbili 32 7 700 3.3 51 Medical C Bahari Beach 15 6100 1.2 20 R Kawawa Rd 8.0 New Kigogo Rd 8.0 Chang ’ombe 6.3 Road SDP office 0.001 Amoutoglu <0.001 Manzese <0.001 Bureau of 4.0 5 300 0.002 0.26 Stds/Ubungo Ardhi Institute <0.001 Radio Tanzania <0.001 DSM Airport 5 200 <0.001 Kivukoni ferry <0.001 Samora Av 9.4 5 400 0.31 Morogoro Rd Oysterbay 5.6 5 300

NO, [pg/m3 ] NOx pg/m3 ] HCOx fpg/m3 ] SPM [mg/m3 ] Location NEMC JICA SDP JICA GEES NEMC GEES NEMC GEES T T T Gerezani 430 20 350 0.69 Kariakoo 250 450 0.76 43 . Askari Mon 250 280 0.19 Muhimbili 200 310 0.61 Medical C Bahari Beach 190 110 0.09 I

15 R Kawawa Rd <74 <61 I New Kigogo Rd <74 <61 Chang ’ombe <74 <61 Road SDP office 28 Amoutoglu 17 Manzese 23 Bureau of 10 56 Stds/Ubungo Ardhi Institute 8 Radio Tanzania 3 DSM Airport 12 1.3 Kivukoni ferry Samora Av Morogoro Rd Oysterbay 60 | The results are not totally comparable. Different lengths of time were used for recording. The time ranges from 10-30 minutes with the Drager equipment to a week with the passive samplers. There are also variations in distance from the measuring spot to the road.

4.4 Analysis of the results Generally, all previousreports seem to be very rushed. They contain many misprints. The measuring methodologies are scarcely accounted for or not described at all. In some of the reports, the calculations leading to the results are faulty. Some of the conclusions are wrong. Values can be inconsistent from one part of a report to another. It is important to be aware of the inpreciseness of the Drager method. Even if you are verycareful with the analysis, you may still have an inaccuracyof up to 50 %. Some of the pollution levels in the reports may be inaccurate since they are out of measuring range. CO must be recorded at a relative humidity of maximum 60 %. S02 needs to be measured at 15-30°C. These conditions are usually not fulfilled. The Drager method is for measurements up to 15 minutes. Some of the reports state much longer periods of measurement. Another thing that makes it difficult to compare results from different studies is the lack of information about where the air sample is taken. All this gives a verydiffuse picture of what the results stand for, with an exception of the NILU-study.

16 5. Our measurements The aim of our measurements was first of all to establish the concentrations of various air pollutants on a busy city street. Second of all, we wanted to set an example on how to start gathering simple meteorological- and traffic related data. With a full set of data it could in the future be possible to at a greater extension use computer models to establish streetlevel air pollution in Tanzania.

5.1 Type of measuring equipment Air pollution was measured with two types of passive samplers and their holders. The first type was used for measuring NO, N02, SOz and 03 . The second type was for monitoring VOC. On the holders for NO, N02, S02 and 03 rainshield are mounted. All samplers were mounted on a streetlight. The samplers require a good air supplyaround their inlet. For measuring traffic flow et.c. a measuring tape and a stop watch were used. The temperature was registered with a thermometer mounted on a streetlight. The wind was measured using a digital wind velocity meter with a detector held in level with the air pollution samplers

5.2 Choice of measuring spot The choice of measuring spot was made according to the instructions given by IVL. They suggested a spot close to a busy road and a place where many people reside. It was instructed to put up the equipment about 20 m before a signalised intersection. Preferably the road should be rather narrow and lined with high buildings to form a “street canyon”, where the air is fairly still. Samora avenueseemed to be the best alternative. It is the main shopping street in Dar es Salaam and therefore has many pedestrians on the pavements and heavy traffic in both directions. The equipment was attached to a streetlight some 40 m before the junction on the predominant lee side of the road.

Our measuring spot seen from north-east

17 5.3 Results from air pollution measurements Air pollution measurements were made in September and October 1997.

Molecular Week 1 (+27°C) Week 2 (+25°C) weight g/mol pg/m3 ppb pg/m3 ppb Sulphur 64.06 67.4 25.9 65.0 24.8 Dioxide Nitrogen 30.01 92.0 68.8 124.0 92.8 Monoxide Nitrogen 46.01 42.8 22.9 44.6 23.7 Dioxide Ozone 48.00 29.6 15.2 I 30.7 15.6 Benzene 1 78.11 23 7.3 24.1 7.5 Toluene 92.14 46 12.3 49.6 13.2 Octane | 110.20 7 1.6 9.2 2.0 Buthylacetate 116.16 1 0.2 0.5 0.1 Ethylbenzene 106.17 12 2.8 10.2 2.4 MP-Xylene I 106.17 34 7.9 34.6 8.0 O-Xylene 106.17 13 3.0 13.4 3.1 Nonane | 124.22 5 1.0 | 5.8 1.1

5.4 Results from meteorological measurements

5.4.1 Temperature readings To get an accurate average temperature on the measuring week, the temperature was recorded every hour between 8-18 and every third hour between 18-6. The thermometer was attached to the same streetlight as the air pollution samplers. All temperatures are given in °C. The first measuring week had no rain, but the second week had some rain on three of the days. The average temperature of week 1 was 26.7°C. The average temperature of week 2 was 25.9°C.

5.4.2 Wind velocity readings The wind velocity was measured on three occasions each measuring week. A wind velocity meter with a detector was used. The detector was held in level with the air pollution samplers while recording. The velocity was recorded every 30 seconds for 15 minutes. The wind velocity had an average of 0.7 m/s and a maximum of 3.5 m/s for week 1. The second week had 0.6 m/s and 3.1 m/s respectively.

5.5 Measurements of traffic During one hour, all motor vehicles passing the measuring spot were recorded. The vehicles were divided into seven different categories. Two measurements were made, both performed during non-rainy conditions. In the JICA 1995 study, daily- and weekly variations could be found. With assistance of these factors the daily traffic in

18 measurement 1 and 2 equalled approximately 12 000 vehicles. Data below are for both directions. Contribution of vehicle types Total measurement 1 and 2 percentage Sedan 783 49.1% 4WD 350 21.9% Pickup/Minibus 332 20.8% 3.5 ton Truck/Bus 24 1.5% 7 ton Truck/Bus 14 0.9% 10-20 ton Truck 3 0.2% Motorcycle 90 5.6% Total 1 596 100.0%

Besides traffic flow, measurements of acceleration/retardation and average speed were performed. The average speed for both directions was 20 km/h.

5.6 Analysis of the results To get a full picture of the pollution concentration one must monitor the pollution for a long period of time. Tough this is not the case here, it can be assumed that the traffic intensity and emissions are roughly constant over the year. This gives a possibility to estimate the yearly average of a pollutant with fewer measurements. Pollution levels tend to decrease during rainy conditions. The weather conditions during our measuring weeks represent a good yearly average. Thereby our measurements can be roughly comparable with a yearly average. When comparing the results from our measurements with guidelines and air pollution standards you get a clearer picture of the severity of the pollution levels.

Our measurements compared with standards for yearly average:

I Pollutant Our Standards Remarks measurements [pg/m3] fug/m3 ] SO? 66 50 For protection of human health N02 108 40-50 For protection of human health SO? 66 30 For protection of human plants NO? 108 30 (NO+N02) For protection of human plants °3 30 50 For protection of human plants

The result above show levels somewhat exceeding the guidelines. The levels can not be said to be alarmingly high, but bearing the rapid increase in the number of vehicles in mind, air pollution will soon be a major problem. What our measurements lack the most is the capability to monitor lead, particles and carbon monoxide, especially measurements of particles seem to be of great importance, judging of indications from earlier studies. Another deficit is the choice of measuring spot. If one had had the possibility to measure air pollution at several other locations, there could have been a clearer picture of the air pollution levels in the city. As it is now the effects from heavy-duty diesel vehicles like busses or trucks are very little accounted for. Measurements of traffic flow and vehicle speed seem to correlate well with data found in 1993 by JICA.

19 There is a need for continuous monitoring of air pollution in Dar es Salaam. Traffic measurements could be easier and more precise if it was possible to use automatic instruments. With that kind of equipment, it is suggested to perform yearly recordings of traffic flow all over city.

20 6. Computer models on traffic related air pollution There are several computer models dealing with traffic related air pollution on the market. When using the models you put in a set of parameters like traffic flow and the roads ’ geometry and out of the program come the concentrations of CO and N02. When the model is calibrated, you have a fast and very cost-effective wayof estimating the roadside concentration of air pollution. The computer model can give an indication of where it is most urgent to concentrate the efforts to reduce air pollution or it can be a valuable tool for judging scenario studies.

6.1 Description of Swedish and Dutch models

6.1.1 The SNV model The SNV-model is validated for Swedish conditions. After extensive studies a version of the model has also been validated for Danish conditions. The model uses a lot input data of which some are rather difficult to collect. On the other hand the program is easy to handle and it gives quite reliable values for CO and N02. The program assumes the calculation point is at least 25 m from an intersection, 3m above ground and 1-2 m from the building. The parameters used to calculate traffic related streetlevel air pollution in the SNV 2 model are:

Compulsory parameters Possible to use predefined values Calculation point Background level CO Calculation year Background level NOg Traffic flow Other CO-sources’ part of background level Maximum hourly traffic flow Other N02-sources' part of background level Type of street City traffic work calculation year/1990 Height of surrounding buildings Percentage maximum hourly traffic of yearly daily average Street width Average speed Number of traffic streams Percentage of vehicles: Distance between calculation point and Accelerating first traffic stream Distance between calculation point and Retarding second traffic stream City size Not having reached working temperature Street location Cars without catalyser Temperature Cars with catalyser Wind conditions Cars diesel driven Trucks petrol driven <3.5 tons Trucks diesel driven <3.5 tons Trucks diesel driven 3.5-7 tons Trucks diesel driven 7-16 tons Trucks diesel driven 16-30 tons Trucks diesel driven >30 tons 1 Light trucks

21 6.1.2 The CAR International model CAR International was originally created for Dutch conditions but have rather successfully been tested in other countries like United Kingdom and China. The model uses few input parameters and it is often possible to use default values. A set of standard road types, speed types and tree factor is available to choose from. Some of the default values are possible to change by the user.

I Required input data Factors user can change Number of vehicles per day Emission factors for CO, NOX, benzene, Pb, smoke and a user-defined substance Percentage of heavy-duty traffic Percentage of N02 directly emitted Speed type Background concentrations Road type Average wind speed Tree factor City diameter Distance from road axis to exposure area

The model is relatively easy to use and parameters needed are easy to collect. The disadvantage with few and simple input parameters is the lack of accuracy.

6.2 Possibilities of application in Tanzania As mentioned before, measuring air pollution citywide is very expensive. Therefor computer models are a cost-effective method to estimate streetlevel air pollution. Because of fewer parameters and simpler handling the CAR-model seems to be the better choice for Dar es Salaam. None of the two models mentioned above are calibrated for Tanzanian conditions and it will probably take some effort before it can be used. The results from computer models might be useful to compare levels at different spots but may not be possible to compare with standards and guidelines.

Geometry of our sampling spot

22 7. Measures to reduce air pollution in Dar es Salaam Dar es Salaam cityis fortunate to be surrounded by an area of mangrove swamps, green fields and trees, forming a green belt around the city. Trees and other plants help filter the air pollution and provides oxygen. This green belt is an inestimable resource that has to be preserved for the future.

It is a big step from measuring air pollution at one spot to finding means to improve the air quality. Nevertheless some general measures are suggested below.

7.1 General measures to reduce traffic • Build parking areas at cityentrances and combine them with good possibilities to change to public transport. • Increase the parking fees in the city centre. • Increase petrol and diesel prices to the benefit of public transport. Through taxes money could be transferred from fuelprices to the upbuilding of a reliable public transport system. • Introduce a system of trams/commuter trains between the city centre and the suburbs. To enable this there first has to be an improvement of Tanzania ’s energy supply. • Get rid of the majority of the minibuses and introduce more full size buses. This would provide a safer, more efficient and less pollutive public transport system.

7.2 Measures to reduce emissions from traffic • Introduce more one-way streets in the city centre to make the traffic flow more smoothly. • Compulsory vehicle inspections each year would reveal cars with emission exceeding predetermined emission levels of carbon monoxide. • Inform the public about economic driving patterns and adjustments of engine to decrease fuel consumption.

23 7.3 Measures to reduce specific air pollutants Standards of fuel quality need to be improved, especially what concerns the content of sulphur and lead. Lead needs to be phased out and unleaded petrol needs to be introduced to provide the means for cars with catalytic converters. In addition, the sulphur content in petrol has to decrease. To help prevent the upcoming of suspended particles more road has to be paved, especially in the city.

24 8. References

8.1 Books and reports Ardhi Institute, Department of Environmental Engineering (1996). Automobile Air Pollution in Dor es Salaam City, Tanzania, Dar es Salaam Tanzania. Bridgeman, H.A. (1990). Global Air Pollution: Problems for the 1990s, Belhaven Press, London Bureauof Statistics (1988). 1988 Population Census: Preliminary Report Centre for Energy, Environment, Science and Technology (1996). Dar es Salaam Air Quality, Dar es Salaam Tanzania. Harrison, M. (1990). Pollution: Causes, Effects and Control. Second Edition, The Royal Society of Chemistry, Cambridge U.K. Japan International Cooperation Agency (1995). The Study on Dar es Salaam Road Development Plan, Final Report, Ministry of Works, Communication and Transport, Dar es Salaam Tanzania. Naturvardsverket (1997). http://www.environ.se/ University of Dar es Salaam, Chemistry Department (1993). Urban Air Quality Monitoring-Pilot Project, National Environmental Management Council, Dar es Salaam Tanzania. Whitelegg, J (1993). Transport for aSustainable Future. The Case for Europe, Belhaven Press, London U.K. Wingqvist, A (1996). Utlandsrapport frdn Sveriges tekniska attacheer. Hallbara transportsystem i USA, Los Angeles USA

8.2 Newspapers and magazine articles The East African Jan 30-Feb 5,1995, page 32 Drager Review 78 February 1997, pages 6-17 Ratten no 2/1998, page 50 National Museum, Dar es Salaam

8.3 Personal interviews Biswaro, Jackson M. Chief Progr amme Officer at Japan International Cooperation Agency Dar es Salaam Revenue Office John, Geoffrey (PhD) at University of Dar es Salaam Katima, J.H.Y. Professor at Chemical Engineering, Universityof Dar es Salaam Kirenga, A.P. at Factory Inspectorate Kitilla, Martin L.D. Executive Engineer (Civil)/Town Planner at Sustainable Dar es Salaam Project Magashi, Anne N. Deputy Director (Information & Policy) at Cleaner Production Centre of Tanzania Migiro, Cleophas L.C. (Prof.) Director at Cleaner Production Centre of Tanzania Mndewa, Benelias S.E. Deputy Director (Demonstration & Training) at Cleaner Production Centre of Tanzania Mnose, Mbwana Sales Assistant at The East African National Newspaper Ltd Mujwahuziat Ministry of Works Mushi, Aloyce P. Managing Director at Co-architecture Norrby, Charlotta Economist at Embassy of Sweden Nyaoro (PhD) Senior Lecturer at Transportation Engineering Dept., University of Dar es Salaam

25 Purdon, Alec Operations Manager at BP Tanzania Rufunjo, Bartholomew B. (PhD) Director of Transport at Ministry of Communication and Transport Svanberg, P. A. Swedish Environmental Research Institute