Institute FOR Systems Engineering Informatics
JOINT RESEARCH CENTRE EUROPEAN COMMISSION
JOINT RESEARCH CENTRE EUROPEAN COMMISSION Institute for Systems Engineering and Informatics
ÇjfU /»«134 Air Quality Indicators f or A\VN Environmental Impact Assessment
'StfO A.Zanetta (Ispra Trainee)
1994 Report EUR 15864 EN LEGAL NOTICE
Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of the following information.
Catalogue: CL-NA-15864-EN-C
© ECSC-EC-EAEC Brussels · Luxembourg, 1994
Printed In Italy SUMMARY
SUMMARY
This paper deals with air quality indicators. First, the concept of air pollution is introduced and main features of air pollutants are discussed. Features considered are: definition and general concepts, unit, natural and man-made emission sources, diffusion and transport, lifetime in the atmosphere and sinks, effects (local, global, on human health and on vegetation), reference values according to regulations and guidelines. Then, the most important air pollutants are examined with reference to the above features. Finally, the indicator reference values according to EU directives, Italian legislation and WHO guidelines are reported. The paper is intended as a reference document to implement the "Air" module of the informatie tool INES-EIA being developed at the JRC Ispra to support Environmental Impact Assessment of technological plants. It can also be used as a source of reference data on air quality indicators in performing a wide range of environmental studies.
TABLE OF CONTENTS
TABLE OF CONTENTS
Introduction pagel
1 Atmosphere and Air Pollutants 3 1.1 Atmosphere ....'. 3 1.2 Air Pollutants 5 1.2.1 Definition and General Concepts 6 1.2.2 Unit 8 1.2.3 Emission Sources 8 1.2.3.1 Natural Phenomena 8 1.2.3.2 Man-Made Activities 8 1.2.4 Diffusion and Transport 9 1.2.5 Lifetime in the Atmosphere and Sinks 10 1.2.6 Effects 11 1.2.6.1 Local Effects 11 1.2.6.1.1 Damage to Construction Elements and Other Materials 11 1.2.6.1.2 Visibility Reduction 12 1.2.6.1.3 Photochemical Smog 12 1.2.6.2 Regional Effects 13 1.2.6.2.1 Acid Depositions 13 1.2.6.3 Global Effects 16 1.2.6.3.1 Depletion of Ozone Layer 16 1.2.6.3.2 Greenhouse Effect 16 1.2.6.4 Effects on Human Health 19 1.2.6.5 Effects on Vegetation 19 1.2.7 Reference Values 20
2 Air Quality Indicators 22 2.1 Sulphur Dioxide and Other Sulphur Compounds (SOx) 22 2.2 Nitrogen Oxides (ΝΟχ) and Other Nitrogen Compounds 28 2.3 Carbon Monoxide and Dioxide (CO*) 31 2.4 Volatile Organic Compounds (VOCs) 35 2.5 Heavy Metals and Their Compounds 38 2.6 Suspended Particulate 39 2.7 Chlorofluorocarbons (CFCs) 42 2.8 Carcinogenic Substances 45 2.9 Ozone (03) 45 TABLE OF CONTENTS
3 Indicator Reference Values According to Regulations and Guidelines 49 3.1 Regulations 49 3.1.1 Air Quality 49 3.1.2 Emissions from Industrial Plants 58 3.2 Guidelines 66 3.2.1 HumanHealth 66 3.2.2 Vegetation 66
References 69 Legislation and Guidelines 69 Articles and Books 70
Abbreviations and Acronyms 74
π LIST OF FIGURES
LIST OF FIGURES
Fig. 1 Composition of the atmosphere Fig. 2 Layers of atmosphere: variation of temperature and density as a function of altitude Fig. 3 Air quality: sources of pollutants, atmospheric interactions and receivers Fig. 4 Transfer of an air pollutant to the other compartments of biosphere as far as man Fig. 5 Different types of aerosols characterised according to their process of origin Fig. 6 Most important emission sources of atmospheric pollutants Fig. 7 Composition of a photochemical smog Fig. 8 Mechanism of photochemical air pollution fromemissio n to deposition Fig. 9 Definition of deposition on the basis of the process that causes it and on the basis of the view point of depositing compound or receiving surface Fig. 10 Scheme of the possible deposition pathways for sulphur dioxide and nitrogen dioxide Fig. 11 Changes in concentration of atmospheric gases Fig. 12 Greenhouse gases and their importance for climate Fig. 13 Trends in surface air temperature during the last century Fig. 14 The greenhouse effect and its possible impact on sea level Fig. 15 Degree ofinjury to man in an air pollution episode depending on the exposure time Fig. 16 Schématisation of a method for the evaluation of impact on health of toxic and cumulative micropollutants Fig. 17 Effects of SOx on materials: materials attacked and related damage Fig. 18 Effects of different concentrations of sulphur dioxide on man Fig. 19 Health effects due to various exposures to S02 Fig. 20 Effects of S02 on vegetation Fig. 21 Relative sensitivity of woody species to S02 Fig. 22 Level of NOx in unpolluted air and in polluted air Fig. 23 Effects of nitrogen dioxide on man Fig. 24 Level of CO in unpolluted air and in polluted air Fig. 25 Maximum CO concentrations and exposure times to prevent the COHb level exceeding 2.5 - 3% (taken from WHO guidelines) Fig. 26 Level of C02 in unpolluted air and in polluted air Fig. 27 Physiological effects of increased C02 on plant growth Fig. 28 Calculated tropospheric lifetimes of selected biogenic VOCs due to reaction with
OH and N03 radicals and ozone Fig. 29 Calculated tropospheric lifetimes of selected anthropogenic VOCs due to photolysis and reaction with OH and N03 radicals and ozone Fig. 30 Content of SP in unpolluted air and in polluted air Fig. 31 Sources of pollutants and most representative particulate bound compounds Fig. 32 Deposition velocity of particles as a function of their size Fig. 33 Fractional amounts of particles of various size deposited in the different areas of the respiratory tract
in LIST OF FIGURES
Fig. 34 Destruction mechanism of the stratospheric ozone following the release of CF2C12 in the environment Fig. 35 Substances that deplete the ozone layer Fig. 36 Effects of ozone on some materials Fig. 37 Relative sensitivity of woody species to ozone Fig. 38 Guide Values for sulphur dioxide expressed in /tg / m3 Fig. 39 Guide Values for suspended particulate (measured by black-smoke method) expressed in /¿g / m3 Fig. 40 Limit Values for suspended particulate (measured by black-smoke method) expressed in ¿ig / m3 Fig. 41 Limit Values for sulphur dioxide with the associated values for suspended particulate (measured by black-smoke method) expressed in /¿g / m3 Fig. 42 Limit Values for sulphur dioxide with the associated values for suspended particulate (measured by gravimetric method) expressed in pg / m3 Fig. 43 Limit Value of acceptability of the concentrations and maximum exposure limits for air pollutants outside Fig. 44 Limit Value of the concentrations in air of precursors of the pollutants shown in Fig. 42, to adopt in certain conditions Fig. 45 Limit Value for nitrogen dioxide expressed in /¿g / m3 Fig. 46 Guide Values for nitrogen dioxide expressed in μ% I m3 Fig. 47 Guide Values of sulphur dioxide, nitrogen dioxide and suspended particulate for air quality Fig. 48 Limit Values of sulphur dioxide and nitrogen dioxide for air quality Fig. 49 Attention levels and alarm levels for air pollutants in large urban zones Fig. 50 Thresholds for ozone concentrations in the air Fig. 51 Sulphur dioxide emission limit values for new plants which use solid fuel Fig. 52 Sulphur dioxide emission limit values for new plants which use gaseous fuel Fig. 53 Sulphur dioxide emission limit values for new plants which use liquid fuel Fig. 54 Nitrogen oxides emission limit values for new plants according to the type of fuel used Fig. 55 Dust emission limit values for new plants according to the type of fuel used Fig. 56 Sulphur dioxide emission limit values for new plants which use solid fuel Fig. 57 Sulphur dioxide emission limit values for new plants which use liquid fuel Fig. 58 Sulphur dioxide emission limit values for new plants which use gaseous fuel Fig. 59 Nitrogen oxides emission limit values for new plants which use solid fuel Fig. 60 Nitrogen oxides emission limit values for new plants which use liquid fuel Fig. 61 Nitrogen oxides emission limit values for new plants which use gaseous fuel Fig. 62 Dust emission limit values for new plants according to the type of fuel used Fig. 63 Emission limit values for dust, heavy metals, hydrochloric acid, hydrofluoric acid and sulphur dioxide (expressed in mg / Nm3) as a function of the nominal capacity of the incineration plant Fig. 64 Air quality guidelines to protect human health Fig. 65 Air quality guidelines to protect vegetation
IV FOREWORD
FOREWORD
This report is a revision of a previous paper on the same subject by Dr. Alessandra Zanetta, a biologist who, after obtaining her degree, spent one year at the JRC Ispra, Institute for Systems Engineering and Informatics. Thanks are due to Dr. Bruno Versino and Dr. Emile De Saeger of the Environment Institute, JRC Ispra, for helpful comments on the previous paper. Thanks are also due to Prof Stefano Cernuschi, Polytechnic of Milan, for very general comments and advice on several specific points.
The report is intended to be a reference document on indicators and indices of air quality, particularly for people involved in Environmental Impact Assessment.
Alessandro G. Colombo
INTRODUCTION
INTRODUCTION
Directive 85/337/EEC introduced the Environmental Impact Assessment (EIA) of certain public and private projects. Each EU member State transposed the directive into national legislation. In Italy, the main reference regulations are the two decrees DPCM No. 377,10/08/1988 and DPCM 27/12/1988.
EIA procedures and methods are described in various books (see, e.g. Polelli M., 1989; Gisotti G. and Bruschi S., 1990; Malcevschi S., 1991; Colombo A.G., 1992). Key parts of an EIA study concern the description of the area affected by the project and the identification and evaluation of impacts. To perform these tasks environmental indicators are needed. An environmental indicator is a parameter which can concisely represent the state of an environmental component.
This paper deals with indicators of air quality. It is intended as a reference document to implement the "Air" module of the informatie tool INES-EIA being developed at the JRC Ispra to support Environmental Impact Assessment of technological plants (Colombo A.G., 1994). Other reference documents have already been produced (see, e.g. Zanetta Α., 1993; D'Eredità L., 1994).
Chapter 1 starts with a brief description of the atmosphere. Then the definition of air pollution is introduced and the main features of air pollutants are discussed. The following features are considered:
DEFINITION AND GENERAL CONCEPT UNIT EMISSION SOURCES DIFFUSION AND TRANSPORT LIFETIME IN THE ATMOSPHERE AND SINKS EFFECTS REFERENCE VALUES
As emission sources, both natural phenomena and man-made activities are taken into account. As local effects, the following effects are considered: damage to construction elements and other materials, degradation of visibility and photochemical smog. Acid depositions are the regional effects considered. For the global effects, the depletion of ozone layer and the greenhouse effect are examined. Effects on human health and on vegetation are also analysed.
Chapter 2 discusses the main air quality indicators. The pollutants considered are the following:
• SULPHUR DIOXIDE and Other SULPHUR COMPOUNDS (SO*) • NITROGEN OXIDES (ΝΟχ) and Other NITROGEN COMPOUNDS • CARBON MONOXIDE and DIOXIDE (COx) INTRODUCTION
VOLATILE ORGANIC COMPOUNDS (VOCs) HEAVY METALS and their compounds SUSPENDED PARTICULATE CHLOROFLUOROCARBONS (CFCs) CARCINOGENIC SUBSTANCES OZONE (O3)
Each pollutant is examined separately with reference to the features discussed in Chapter 1, except reference values that are discussed in Chapter 3.
Chapter 3 includes two sections. The former reports figures from EU directives and Italian legislation that concern the protection of air quality and the control of emissions from industrial plants. The latter reports figures from WHO Guidelines intended to protect human health and vegetation.
As known, also living organisms (bioindicators) are used to evaluate air quality (see, e.g. Nimis, 1990). Bioindicators allow the drawing of air pollution maps of large areas at a relative low cost. These maps are utilised to optimise the positioning of the recording gauges in high risk areas, where chemical indicators are then measured. However, bioindicators are not yet considered in regulations also because of the degree of error intrinsic to biological data. This is a main reason why, in this paper, the analysis is limited to chemical indicators. part I - ATMOSPHERE AND AIR POLLUTANTS
1 ATMOSPHERE AND AIR POLLUTANTS
First, it should be pointed out here that in this paper the two terms, atmosphere and air, have been used as synonyms.
1.1 ATMOSPHERE
The atmosphere is the gas envelope that surrounds the terrestrial globe. It is constituted of a mixture of gases, suspended particles and water vapour (Fig. 1).
CONSTITUENT FORMULA ABUNDANCE BY VOLUME (percent, ppm, ppb)
Nitrogen N, 78.084 ±0.004% Oxygen o, 20.948 ±0.002% Argon Ar 0.934 ±0.001%
Water vapour Η,Ο Variable (% - ppm) Carbon dioxide CO, 325 ppm Neon Ne 18 ppm Helium He 5 ppm Krypton Kr 1 ppm Xenon Xe 0.08 ppm Methane CH4 2 ppm Hydrogen H, 0.5 ppm Nitrous oxide Ν,Ο 0.3 ppm Carbon monoxide CO 0.05-0.2 ppm Ozone oa Variable (0.02 -10 ppm) Ammonia NH, 4 ppb Nitrogen dioxide NO, 1 ppb Sulphur dioxide SO, 1 ppb Hydrogen sulphide H,S 0.05 ppb
Fig. 1. Composition of the atmosphere. (SchidlowskiM., 1986)
The concentration in the air of each atmospheric constituent is the result of a delicate equilibrium between gains and losses. Besides, its density varies with the altitude. In particular, up to about 100 km, the atmosphere can be considered well mixed and homogeneous; on the other hand, above this altitude, the density of the lighter gases gradually increases. The atmosphere has been divided into four main layers, according to its physical characteristics. See Fig. 2. The lowest part of the atmosphere is called the troposphere. It begins at the terrestrial surface and extends upward to about 10 km altitude. In this layer, the temperature decreases with altitude at the rate of 6 - 8 °K per km. The portion of the part I - ATMOSPHERE AND AIR POLLUTANTS
atmosphere between 10 and 50 km is called the stratosphere. In this layer, the temperature increases with altitude and the density is lower than in the troposphere. As a result the temperature gradient, in the passage from the troposphere to the stratosphere, is direct in the opposite d^ection. The boundary that separates these two layers is named the tropopause. It represents the upper limit of turbulent mixing for atmospheric gases; in fact it is the barrier that prevents the exchanges of chemical species between the troposphere and the stratosphere. Above the stratosphere there is the mésosphère, which is separated from this last by the boundary termed the stratopause. The final layer is the thermosphère, the lower boundary of which is the mesopause. The density always decreases with altitude
Thermosphère.
Mesopause -
Stratosphere "
Concorde/TU144 -Tropopause lOi Subsonic aircraft Temperarure/K^-^.^ \ Troposphere 180 200 220 240 2«Γ"-^280 \ 300 X ■ ' ' ' ' r^*^- * ι v
Fig. 2. Layers of atmosphere: variation of temperature and density as a function of altitude. (Samiullah Y, 1990) part I - ATMOSPHERE AND AIR POLLUTANTS
1.2 AIR POLLUTANTS
The state and behaviour of the atmosphere change in pollution condition. Air pollution has been defined as a condition occurring following the emissions in the atmosphere of substances that alter the state of the air and harm the environment and human health. Pollutants are released in the air from various sources. In the atmosphere they are diluted and may undergo a variety of physical and chemical processes; for example, they react with other atmospheric chemical species or are photodissociated. Besides they may be transported to zones different to those in which they were released. Finally they may return to Earth by means of wet and dry deposition. Fig. 3 shows that air quality is the result of the atmospheric interactions that the polluting emissions undergo once released in air. Moreover it is possible to see that air quality has effects on receivers; this general term represents, at the same time, men, animals, plants, water, soil, landscape, in other words the whole Biosphere. All together, the receivers are those which, at the end, feel the effects of bad air quality more or less seriously. In fact, it is well known that good air quality is of fundamental importance for the welfare of the biosphere. Besides it must be remarked that the various compartments of the biosphere must not be considered as separate and static blocks because transfers of energy and matter already exists amongst them. So, man can directly inhale an air pollutant, but can also ingest polluted food, such as vegetables on to which the pollutant is deposited or, for example, meat from animals which have inhaled polluted air. Fig. 4 illustrates how a pollutant in the air may be transferred to the other compartments of the biosphere as far as man.
ATMOSPHERIC >v INTERACTIONS /
POLLUTING EMISSIONS EFFECTS OF POLLUTION
SOURCES OF RECEIVERS POLLUTANTS
Fig. 3. Air quality: sources of pollutants, atmospheric interactions and receivers. (Gisotti G and Bruschi S., 1990 Translated.) part I - ATMOSPHERE AND AIR POLLUTANTS
PLANTS AND
DEPOSITION VEGETABLES INCÍITIO«
DIM OLIT ION SYNTHESIS
SOIL INCESTION MAN DEPOSITION
DIMOI. IT ION SYNTHESIS
POLLUTANT
INGESTION ANIMALS
INHALATION
Fig. 4. Transfer of an air pollutant to the other compartments of biosphere as far as maa (VismaraR, 1988. Translated.)
1.2.1 DEFINITION AND GENERAL CONCEPTS Air pollutants can be divided into primary pollutants or secondary pollutants. All pollutant substances which are emitted directly into the atmosphere from an identifiable source, are called primary pollutants. The most significant primary macropollutants are the following: CARBON MONOXIDE CO CARBON DIOXIDE C02 . NITRIC OXIDE NO NITROGEN DIOXIDE N02 SULPHUR DIOXIDE S02 SUSPENDED PARTICULATE VOCs Primary micropollutants are: HEAVY METALS PAHS
The secondary pollutants are those generated in the atmosphere by means of chemical processes between two or more primary pollutants or by reaction with normal constituents of the atmosphere, with or without photoactivation. The main secondary pollutants are the following: NITROGEN DIOXIDE N02 NITROUS OXIDE N20 NITRIC ACID HNO3 OZONE O3 SULPHURIC ACID H2S04 VOCS part I - ATMOSPHERE AND AIR POLLUTANTS
As one can see, some pollutants have both a primary and a secondary nature, for example nitrogen dioxide and some VOCs.
From a physical viewpoint, air pollutants can be present in the atmosphere in three different forms: gaseous -» GASES liquid -> VAPOURS liquid-solid -» AEROSOLS
Once dispersed in air, both gases and vapours follow the laws of ideal gases. The situation is more complex for aerosols because they are a mixture of particles of various sizes and composition suspended in air. Aerosols have different names according to their origin (Fig. 5)·
AEROSOL ORIGIN PROCESS
Solid particles formed by fine crushing of a starting material of which they DUST maintain chemical characteristics: fine dusts (diameter < 100 urn) and coarse dusts (diameter > 100 μτη) have been distinguished.
Solid particles formed by condensation of vapours produced, at high temperatures, by combustion or sublimation: diameter 0.001 - 1μπι. They can EXHALATION have the same chemical composition as the starting products or their oxidation forms (metallic oxides). They can also form large aggregates of several particles.
SMOKE Solid and liquid particles of diameter < 0.5 urn, produced by combustion of organic substances. !
MIST (ARTIFICIAL FOG) Liquid particles, of variable size, (0.1 - 50 urn) produced by turbulence of a liquid (spraying, atomisation, spray) or by condensation.
FOG Liquid aerosol produced by condensation at high humidity: sizes > 1 urn.
SMOG Aerosol mixed of fog and smoke.
CONDENSATION Very little particles (diameter < 0.1 urn) produced by processes of combustion NUCLEI and chemical conversion from gaseous precursors ι
Fig. S. Different types of aerosols characterised according to their process of origin. (VismaraR, 1988. Translated and modified.) part I - ATMOSPHERE AND AIR POLLUTANTS
1.2.2 UNIT
The concentration of an air pollutant, like that of the typical atmospheric constituents, can be expressed by means of different units. These are:
VOLUME PER UNIT OF VOLUME (PARTIAL VOLUME) expressed as ppm or better ppmv, 10-6 This unit is much used to compare the concentration of different pollutants because, under standard conditions, the volume of 1 mole of gas is constant (e.g. 1 ppm of N02 has the same number of molecules as 1 ppm of S02).
MASS PER UNIT OF VOLUME expressed as μg / m3 This unit is useful to quantify the concentration of aerosols and particulate because, since they are a mixture of compounds, it is not possible to define a single molecular weight.
MASS PER UNIT OF MASS expressed as μ§ / g This unit is that less commonly used although suggested by SI.
1.2.3 EMISSION SOURCES
Atmospheric pollutants derive from natural phenomena and man-made activities. Fig. shows the most important emission sources of atmospheric pollutants.
1.2.3.1 NATURAL PHENOMENA
Sources of air pollutants are geo-chemical, biological and atmospheric reactions. For example: plants liberate volatile hydrocarbons (terpenes), wildfires free smoke and trace gases, volcanic emissions release sulphur dioxide and suspended particulate, wind transports dust, sea spray frees trace gases and suspended particulate.
1.2.3.2 MAN-MADE ACTIVITIES
Many air pollutants are caused by human activities. For instance, in agriculture, slash burning produces sulphur dioxide, fertilisers liberate nitrous oxide, rice-fields release methane. On the other hand, most manufacturing processes release pollutants to the environment. Yet above all, the most significant source of anthropogenic air pollution is the combustion of fuel for energy production, for example in heating plants and in motor vehicles. part I - ATMOSPHERE AND AIR POLLUTANTS
GEO-CHEMICAL PHENOMENA sea spray from oceans and large lakes volcanoes i» wildfires wind-blown dust
NATURAL BIOLOGICAL PHENOMENA PHENOMENA *«- bacterial denttrification demolition of organic matter
ATMOSPHERIC PHENOMENA ■*> lightnings
EMISSION SOURCE
biomass burning electrical energy production MAN-MADE fertilised and cultivated soil ACTIVITIES heating plants incinerators industrial processes vehicular traffic
Fig. 6. Most important emission sources of atmospheric pollutants.
To simplify in Fig. 6, wildfires have been considered only as a geo-chemical source of air pollutants; but in reality it is not always possible to decide whether their origin is natural or if they are caused by human activity.
In western Europe, the most significant sources of air pollutants are, in order of importance, the following: ROAD VEHICLES ELECTRIC POWER PRODUCTION DOMESTIC AND INDUSTRIAL HEATING INCINERATORS INDUSTRIAL PROCESSES
To control the air quality, an inventory of the not-mobile and mobile anthropogenic emissions should be made to estimate the type and the amount of pollutants released in the atmosphere. One may suppose that it is more difficult to plan the inventory of the mobile anthropogenic emissions from motor vehicles than that of the non-mobile emissions.
1.2.4 DIFFUSION AND TRANSPORT
Because it has been observed that even zones far from the source of pollution feel the negative effects, the diffusion and transport in the atmosphere of a pollutant are fundamental points in the assessment of the potential danger of a substance emitted into part I - ATMOSPHERE AND AIR POLLUTANTS the air. In the atmosphere, diffusion and transport processes occur simultaneously. They depend on various factors. First of all the type of the emission source must be considered; then meteorological, climatic, geo-morphological and topological parameters play their respective roles.
TYPE OF EMISSION SOURCE The emission source can be: moving or stationary at ground level or elevated isolated or multiple instantaneous or continuous of different geometric configuration (point, linear, area, volume)
METEOROLOGICAL AND CLIMATIC PARAMETERS Relevant meteorological and climatic parameters are the following: temperature (average, maximum and minimum) vertical temperature gradient and the correlated atmospheric stability wind direction and velocity sunshine hours barometric pressure rainfall distribution and regime relative humidity cloud coverage
GEO-MORPHOLOGICAL PARAMETERS These parameters indicate the characteristics of the land.
TOPOLOGICAL PARAMETERS The topology of the site requires the knowledge of the surrounding buildings.
All these parameters must be considered in the modelling of the dispersion and transport of a pollutant in the atmosphere.
1.2.5 LIFETIME IN THE ATMOSPHERE AND SINKS
The lifetime of each air pollutant is determined by the chemical transformations and removal processes which it undergoes in the atmosphere. The most reactive chemical species are OH and N03 radicals and ozone. The lifetime is measured as mean residence time in the atmosphere. Because a high mean residence time signifies that the pollutant remains in the atmosphere for a long time, high values of this parameter correspond with high pollutant danger.
10 part I - ATMOSPHERE AND AIR POLLUTANTS
1.2.6 EFFECTS
In this contest, effects mean the environmental consequences which occur if an air pollutant is released into the atmosphere. When there is more than only one pollutant, the effects due to the combination of several pollutants may be additive, antagonistic or synergistic. Because of pollutant transport in the atmosphere, the effects of the pollution are felt not only in the zone around the emission source, but also far from it. For this reason, it is important to evaluate:
LOCAL EFFECTS due to small emission sources (e.g. low chimneys) effects are felt as far as some 10 km from the emission source
REGIONAL EFFECTS due to big industries and urban agglomerations effects are felt as far as 100 km from the emission source
GLOBAL EFFECTS due to the accumulation of pollutant emissions in time effects are felt from 100 km to 10,000 km from the emission source
1.2.6.1 LOCAL EFFECTS
1.2.6.1.1 Damage to Construction Elements and Other Materials
Air pollution may harm various materials, for example construction elements, fabrics and dyes. There are five mechanisms by means of which air pollutants damage materials (Yocom J.E. and McCaldin R.O., 1977): 1. Abrasion 2. Deposition and removal 3. Direct chemical attack 4. Indirect chemical attack 5. Electrochemical corrosion
The most frequent damage is that due to chemical corrosion. In the atmosphere, sulphur dioxide, nitrogen dioxide and carbon monoxide are converted in acids which then fall on Earth with the depositions (see below Acid Deposition) causing the chemical corrosion of affected materials; stones of building for instance marble, slate, mortar and limestone are particularly affected. Other bad consequences of pollution are: visible soiling of the structures, tarnishing and deterioration of metals, clouding of glasses and smooth surfaces, changes of the colour of paints, abrasion and general weakening of materials such as leather, paper, fabrics and rubber. This phenomenon has economic effects in relation to the cost of protecting the artistic heritage.
11 part I - ATMOSPHERE AND AIR POLLUTANTS
1.2.6.1.2 Visibility Reduction
Visibility reduction is due to absorption, dispersion and scattering of liquid, solid and gaseous particles. In conditions of unpolluted air, visibility can reach over 250 km. It decreases when aerosols and particulate are present; for instance, nitrogen and sulphur oxides, released in the atmosphere, form acid aerosols which interfere with visibility. This aspect of air pollution implies hazards for terrestrial, naval and aerial transport.
1.2.6.1.3 Photochemical Smog
This phenomenon was first recognised in the Los Angeles area in the 1940s, when plants began to show damage. It occurs in large urban areas in hot and sultry periods, and is due to the pollution caused principally by vehicular traffic but also by industrial emissions. Briefly, in the lower troposphere, the VOCs and oxides of nitrogen from vehicular and industrial emissions, react with other chemical species by means of solar radiation to form finally ozone and other oxidant compounds such as peroxyacetyl nitrate (PAN). The accumulation of ozone and these compounds in the troposphere is favoured by slow- moving, high-pressure weather systems; in other words, when one has stagnant air with calm wind or weak winds and high temperature and humidity values. The photochemical smog produced following these reactions is harmful for plants and people. In particular, it causes an increase in the cases of irritation to eyes and throat in man. Fig. 7 illustrates the composition of a photochemical smog, whereas Fig. 8 explains the mechanism of the photochemical air pollution from emission to deposition.
CONCENTRATION (ppb) MORNING VALUES OTHER TIMES carbon monoxide 10,000 nitric oxide 300 midday low 20 nitrogen dioxide 70 midday values 200 nitrogen trioxide 0.1 nitrogen pentoxide 0.2 nitrous acid 0.4 ozone 30 afternoon 200 non-methane hydrocarbons 300 alkenes 30 formaldehyde 100 other aldehydes 50 afternoon 30 PAN 10-50
CONCENTRATION (cm4) hydroperoxy radical 10« hydroxyl radical 10» atomic oxygen 10s atomic hydrogen <1
Fig. 7. Composition of a photochemical smog. (Brimblecombe P., 1986)
12 part I - ATMOSPHERE AND AIR POLLUTANTS
Dry Cloud transformation evaporation RH ♦ OH—>·Η,0 ♦ R. R- -t- Oj + W-+RO, + M RO, -i- NO NO] + RO 3__/ NO, 4-Af—eNO + O Air -Wat translormatlon \ O + O1 + M—«>, + M concentrations O3. NCy. RH «c. <+—* »HOj-^M^D ♦ O} 0)*Hfll-¥20t + t*fl 1 <*p%* ■0p-*lnHOr¡ Initial Tranaport i mixing and diffuslon ¡ Scav»angin g II ΗΝΟ,.Μ,Ο,.ΜΟ.M.O.. HO., I ' 1
I · ' *»l Scavenging ΗΜΟ,.Η,Ο,.ΜΟ» 'l'/¡~', Dry deposition Wat Oj. ΝΟγ. voe II Ι · Ι Ι ι dapoaltlon NO,
•S=ê*¥T-HH*r5ã=wrr
VOCs have been represented as RH.
Fig. 8. Mechanism of photochemical air pollution from emission to deposition. (National Research Council, 1992)
1.2.6.2 REGIONAL EFFECTS
1.2.6.2.1 Acid Depositions
Acid depositions can be wet or dry. In the case of wet deposition, the pollutants are incorporated into cloud, rain, snow or hail and transferred to the ground by precipitation.
13 part I - ATMOSPHERE AND AIR POLLUTANTS
On the other hand, in the case of dry deposition, gases or particles are deposited directly on to terrestrial surfaces (Fig. 9).
PROCESS VIEW POINT OF VIEW POINT OF DEPOSITING COMPOUND RECEIVING SURFACE
precipitation of rain or snow "particles" with A dissolved (soluble) or undissolved wet deposition (unsoluble) content precipitation deposition Β precipitation of particles other than rain or snow according to gravity i impaction of aerosols including fog and C cloud droplets according to air or Brownian dry deposition movement (*) interception deposition D dissolution of gases on wet surfaces (with subsequent chemical reactions)
(*) the impact of fog and cloud droplets is sometimes grouped under wet deposition
Fig. 9. Definition of deposition on the basis of the process that causes it and on the basis of the view point of depositing compound or receiving surface. (Ulrich B., 1983)
The main contributors of acidity are sulphur and nitrogen oxides. They especially come from urban and industrialised zones. Their atmospheric oxidation leads to the formation of sulphuric and nitric acids which are strong acids. They form aerosols and are incorporated into the precipitation elements causing acidification in the depositions. Fig. 10 illustrates the possible deposition pathways for sulphur dioxide and nitrogen dioxide. The middle column shows the substances that form prior to the deposition; whereas the two side columns show the compounds which are included in the wet or dry depositions. Specialised scientific literature reports that acid depositions seem to have a harmful impact on the environment (see e.g. Legge A.H. and Krupa S.V., 1986). In particular in terrestrial ecosystems, the damage affects vegetation and soil. It is observed that acid depositions may increase the susceptibility of plants to abiotic and biotic stress factors; in fact, trees become less resistant to climatic specific conditions (e.g. frost, drought) and to the attack of parasites, such as viruses, bacteria, fungi and insects (Smith W.H., Geballe G. and Fuhrer J., 1984). Regarding soil, it could undergo acidification, the magnitude of which depends on the chemistry of the soil itself. As an
14 part I - ATMOSPHERE AND AIR POLLUTANTS
example, one potential consequence of the soil acidification is the alteration of the activity of the soil microorganisms involved in the process of the nutrient re-cycle; besides, because plant productivity depends on this process too, it is possible to understand how finally soil acidification may have an indirect effect on plant growth (Firestone M.K. et al., 1984). About aquatic ecosystems, it is recognised that lakes with a low buffering capacity, which makes them particularly vulnerable to acidification, suffer the heaviest impact. In fact, ecotoxicological consequences in surface water following the acidification of poorly buffered lakes have been pointed out. As for soil, the acidification of aquatic ecosystems is a function of the chemical nature of the rocks and sediments. Besides, in urban zones, another potential impact of the acid depositions is linked to the effects that they may have on the deterioration of construction elements damaging, for example, the state of monuments.
DRY DEPOSITION SUBSTANCE WET DEPOSITION
S02 «·<- SO,
water so,
2- 2 so*- -«- SO soj- ■► S04 "
water ■► soj" NO I NO, **- NO,
water —— ► NO, I X -4. PAN -·*- PAN PAN I HN03 «·*■ HNO. I τ J NO; ►NO; water ■► NOJ
important pathways uncertain pathways
Fig. 10. Scheme of the possible deposition pathways for sulphur dioxide and nitrogen dioxide (Samiullah Y, 1990. Modified.)
15 part I - ATMOSPHERE AND AIR POLLUTANTS
1.2.6.3 GLOBAL EFFECTS
1.2.6.3.1 Depletion of Ozone Layer
The greatest concentration of ozone is present in the stratosphere. Here, the ozone has a critical role in absorbing ultraviolet solar radiation, preventing its penetration to the Earth's surface. In fact, the potential mutagenic effect of UV on the biological molecules is well known. Some chemicals, for example the CFCs (see section 2.7), interfere with the equilibrium of synthesis and destruction to which the ozone is subject in the atmosphere. These compounds prime a chain of reactions which leads to the removal of the ozone. Then, finally, the effect of a reduction of the atmospheric ozone layer causes an increase of the penetration of the UV which involves injuries to biological structures. Man, animals and plants are the targets. In particular, as examples, the following effects seem to be possible consequences of the depletion of the ozone layer:
MAN an increase of the cases of skin cancers an increase of the cases of eye cataracts
PLANTS a reduction of the photosynthesis rate a reduction of the efficiency of water consumption a reduction of the foliar areas
AQUATIC ECOSYSTEMS a reduction of phytoplanktonic productivity
1.2.6.3.2 Greenhouse Effect
The greenhouse effect is related to the "global climate change". This term refers to changes in atmospheric chemistry and climate due to the increasing emission into the atmosphere of some gases, in particular carbon dioxide, nitrous oxide, methane and chlorofluorocarbons. Fig. 11 shows the changes in concentration of atmospheric gases which occurred from the pre-industrial epoch to the last ten-year period. The role that each gas plays on the climate is illustrated in Fig. 12. It is possible to see that these gases act as greenhouse gases. In fact, they absorb the IR from the Earth's surface and atmosphere, and reradiate a portion of that energy back to the Earth. The increasing atmospheric concentration of greenhouse gases alters the radiative energy balance of the Earth causing the increase of the global mean surface air temperatures (Fig. 13). Finally, this general warming of the Earth would cause serious changes in the climate with various adverse impacts, such as an increase of the sea level, as Fig. 14 shows (MacCracken M.C. and Grotch S.L., 1989; Mitchell J.F.B., 1989; Ramanathan V, 1989).
16 part I - ATMOSPHERE AND AIR POLLUTANTS
SPECIES MEAN GLOBAL C ONCENTRATION ANNUAL RATE OF INCREASE PRE-INDUSTRIAL CIRCA 1987 DURING 1980s
CO, ~ 280 ppm 348 ppm 0.5%
CH¿ - 600 ppb 1,680 ppb 0.8%
Ν,Ο ~ 285 ppb 307 ppb 0.2%
CFCI, 0 240 ppt 4%
CF,CI, 0 415 ppt 4%
CCI4 0 140 ppt 1.5%
CH,CCI3 0 150 ppt 4%
CH,CI 600 ppt ? 600 ppt -0%
CO ? 90 ppb -1 % (northern hemisphere) < 1 % (southern hemisphere)
Fig. 11. Changes in concentration of atmospheric gases. (National Research Council, 1992)
Trace constituent Common name Importance for climate CO, Carbon dioxide Absorbs infrared (IR) radiation; affects stratospheric O3 QJ Ozone Absorbs ultraviolet (UV) and IR radiation CHt Methane Absorbs IR radiation; affects tropospheric 03 and OH; affects stratospheric O3 and H20; produces C02 N20 Nitrous oxide Absorbs infrared radiation; affects stratospheric O3 CFCI3 CFC-11 Absorbs infrared radiation; affects stratospheric O3 CF2a2 CFC-12 Absorbs infrared radiation; affects stratospheric O3 QF3C13 CFC-113 Absorbs infrared radiation; affects stratospheric O3 CjFsa CFC-115 Absorbs infrared radiation; affects stratospheric O3 Absorbs infrared radiation; affects stratospheric O3 CHF2C1 HCFC-22 ca« Carbon tetrachloride Absorbs infrared radiation; affects stratospheric O3 CHjCCb Methyl chloroform Absorbs infrared radiation; affects stratospheric O3 OH Hydroxyl Scavenger for many atmospheric species, including CH4, CO, CH3CCI3, and CHF2C1 CO Carbon monoxide Affects tropospheric O3 and OH cycles; produces CO2 NO, Nitrogen oxide Affects O3 and OH cycles; precursor of acidic nitrates CF2ClBr Ha-1211 Absorbs infrared radiation; affects stratospheric O3 CF3Br Ha-1301 Absorbs infrared radiation; affects stratospheric O3 SO2 Sulfur dioxide Forms aerosols, which scatter solar radiation (CHj)^ Dimethyl sulfide Produces cloud condensation nuclei, affecting cloudiness and albedo QH^ etc NMHC Absorb infrared radiation; affect tropospheric 03 and OH COS Carbonvl sulfide Forms aerosol in stratosphere which alters albedo
Fig. 12. Greenhouse gases and their importance for climate. (Wuebbles D.J. and Edmonds J., 1991)
17 part I - ATMOSPHERE AND AIR POLLUTANTS
Fig. 13. Trends in surface air temperature during the last century. (National Research Council, 1992)
CHANGE IN OCEAN VOLUME
MELT OF GLACIERS
ACCUMULATION ON POLAR ICE SHEETS PERTURBATION OF co RELATIVE IEA LEVEL THERMAL EXPANSION OF OCEAN WATER
DISINTEGRATION W AIS
DYNAMIC RESPONSE OF SOLID EARTH: ELASTIC (INSTANTANEOUS) VISCOUS (SLOW)
Only the most important factors are indicated.
Fig. 14. The greenhouse effect and its possible impact on sea level. (Oerlemans J., 1989)
18 part I - ATMOSPHERE AND AIR POLLUTANTS
1.2.6.4 EFFECTS ON HUMAN HEALTH
Pollutants penetrate the human organism via inhalation. The main target is the respiratory system. The illnesses vary from allergic forms to pulmonary cancer. The degree ofinjury depends on the exposure time; so it is possible to separate short-term exposure effects and long-term exposure effects. Generally, the degree ofinjury, depending on the exposure time, is as reported in Fig. 15.
EXPOSURE TIME DEGREE OF INJURY
seconds - minutes disagreeable odours, reduced visibility, eyes and nose-pharynx irritations
hours - days acute respiratory diseases
months - years chronic respiratory diseases, pulmonary cancer
Fig. IS. Degree ofinjury to man in an air pollution episode depending on the exposure time.
It should also be pointed out that a group of particularly at risk subjects exists; they are: children, old men, pregnant women, smokers and above all those with chronic illnesses such as asthmatics and people suffering for chronic bronchitis.
1.2.6.5 EFFECTS ON VEGETATION
Pollutants reach plants via wet or dry deposition and also via the soil. Symptoms are grouped into invisible or visible injury. The former are biochemical, physiological and metabolic damage (e.g. decrease of the photosynthesis rate); successively, they often become apparent as macroscopic impairments (e.g. reduction of growth, necrosis) Under stress conditions resulting from air pollution, single plants of different species or varieties, but even individuals of the same population, respond with a different degree of sensibility and, as a consequence, the damage will be different. Resistance to the injury also depends on the stage of development of the plant and on external conditions, such as soil and climate. Besides, it has been found that in condition of pollution plants became less resistant to the other environmental stresses, such as frost or pathogenies. Air pollution may also have an effect on the composition and structure of ecosystems which may undergo variations because of the different tolerance to pollution of the organisms.
19 part I - ATMOSPHERE AND AIR POLLUTANTS
All the above-mentioned effects, caused by air pollution, involve, finally, a drop in food crop production and damage to ornamental plants with obviously a negative effect in economic terms.
1.2.7 REFERENCE VALUES
Reference values for air pollutants have been determined with the aim of protecting the environment. These values are defined pollutant concentration; they can be expressed as Guide Value or as limit Value. The former represents the level to be aimed to safeguard the environment, while the latter is the threshold level that must never be exceeded. The reference values reported in this paper have been taken from both legislation and guidelines. Regarding legislation, a first approach to the problem of air quality protection was the implementation of decrees that formulated reference values for pollutants in the air. These values must therefore be applied in air quality monitoring. Following this, because good air quality is the result of the control of pollutant emissions, environmental policy also concentrated on the drawing up of reference values for pollutants measured at the emission source. So, other laws, focused on the emissions from industrial plants, from mobile sources (traffic) and from civil use, have been produced. Air quality guidelines deserve a separate comment. In fact, guidelines do not have legislative value. They suggest values formulated by the scientific world to form the background information useful to authorities in management decisions. The WHO guidelines (WHO, 1987), which have been used in preparing this paper, have the goal of protecting the environment from the harmful effects of air pollution and to control those pollutants that are hazardous to human health. The procedure for evaluating the risk to human health is schematised in Fig. 16. The experimentally obtained value represents the guideline value; it indicates the level, combined with the exposure time, at which no adverse effect is expected; but there is no guarantee that highly sensitive subjects will not be affected at concentration levels lower than this.
20 part I - ATMOSPHERE AND AIR POLLUTANTS
EMISSION SOURCE
Identification of toxic and cumulative atmospheric micropollutants
Emissions characterization
Transport and distribution Climatology and terrain of the emitted pollutants features of the area in the area of concern
Evaluation of human exposure Land utilization (residential, through multiple pathways recreative, agricultural, etc.)
Evaluation of human Analysis of dose-response health risk relationship of micropollutants
Fig. 16. Schématisation of a method for the evaluation of impact on health of toxic and cumulative micropollutants. (Cemuschi S. and Giugliano M., 1992)
21 part Π - AIR QUALITY INDICATORS
2 AIR QUALITY INDICATORS
The absence or presence, with relative quantification, of a pollutant in the air gives concrete information about the air quality, so air pollutants are consequently air quality indicators. From scientific literature and also from the proposal for a Council Directive on integrated pollution prevention and control discussed in Brussels on 14 September 1993, it appeared that the most widespread and harmful air pollutants are the following:
SULPHUR DIOXIDE and Other SULPHUR COMPOUNDS (SO*) NITROGEN OXIDES (NO*) and Other NITROGEN COMPOUNDS CARBON MONOXIDE and DIOXIDE (COx) VOLATILE ORGANIC COMPOUNDS (VOCs) HEAVY METALS and their compounds SUSPENDED PARTICULATE CHLOROFLUOROCARBONS (CFCs) CARCINOGENIC SUBSTANCES OZONE (03)
2.1 SULPHUR DIOXIDE AND OTHER SULPHUR COMPOUNDS (SO,)
Definition and General Concepts Sulphur dioxide (S02) and sulphur trioxide (S03) are the sulphur oxides (SOx). S02 is a colourless gas with biting odour. In the atmosphere S02 is oxidised to S03 which reacts with OH ions to form sulphuric acid (H2S04) and sulphate (S04~) aerosols. Then they return to earth through wet or dry deposition (acid depositions). The presence in the air of SO2 is due to the combustion of sulphur-containing fuels. For this reason, the concentration of sulphur dioxide in industrialised areas is greater than that measured in lands covered by vegetation. At present, fuels have a sulphur content equal to or less than 1%. Therefore the increase of the employment of methane as fuel, helps to keep S02 emission in the atmosphere under control.
Unit Conversion factors for S02 (WHO, 1987): 1 ppm = 2,860 μg / m3 lmg/m3 = 0.35 ppm
Emission Sources NATURAL SOURCES Biological process of demolition of organic matter in oxidising conditions. Volcanoes. MAN-MADE SOURCES Combustion of sulphur-containing fossil fuel in thermal plants. Industrial processes, such as smelting of ores. Biomass burning.
22 part II - AIR QUALITY INDICATORS
Lifetime in the Atmosphere and Sinks Mean residence time in the atmosphere: from 1 to 2 days (Beilke S., 1987). The most important sink is due to loss through wet and dry deposition.
Local Effects Damage to Construction Elements and Other Materials: see Fig. 17. Visibility Reduction
MATERIAL ATTACKED DAMAGE
FERROUS METALS corrosion
COPPER corrosion formation of verdigris
ALUMINIUM corrosion formation of aluminium sulphate (white)
MATERIALS FOR BUILDING leaching (limestone, marble, slate, mortar) weakening
LEATHER embrittlement
PAPER embrittlement
NATURAL and SYNTHETIC FABRICS reduction of resistance to traction deterioration
Fig. 17. Effects of SOx on materials: materials attacked and related damage. (VismaraR, 1988. Translated and modified.)
Regional Effects Acid Depositions
Global Effects Greenhouse Effect
23 part n - AIR QUALITY INDICATORS
Effects on Human Health S02 is inhaled by man. It may cause pulmonary diseases such as chronic bronchitis. It has been suggested that S02 increases the airway resistance. The effects that man undergoes when exposed to different concentrations of S02, are reported in Figg. 18 and 19.
CONCENTRATION as ppm (*) EXPOSURE TIME EFFECT
0.03 - 0.05 continuous Aggravation in conditions of bronchial patients
0.3-1 20 s Alteration of cerebral activity
0.5-1.4 1 min Perception of odour
0.3-1.5 15 min Increase of ocular sensitivity
1-5 30 min Increase of resistance to pulmonary ventilation, smell loss
1.6-5 less than 6 h Constriction of nasal and pulmonary ways
5-20 more than 6 h Pulmonary injury, reversible if exposure stops
more than 20 more than 6 h Saturation of pulmonary ways and tissues, that can in some cases lead to palsy and / or death
(*) Generally lower if there are also aerosols, particulate and other pollutants.
Fig. 18. Effects of different concentrations of sulphur dioxide on man. (Mosello R. et al., 1993. Translated.)
WHO guidelines have suggested the following maximum values for S02 to protect public health (WHO, 1987): 500 μg/m3 for an exposure time of 10 minutes 350 μg / m3 for an exposure time of 1 hour
24 part Π - AIR QUALITY INDICATORS
10 yr
1 rno -
4 days Increased incidence of y^>\\> \ \ 6 Ci 5 cardiorespiratory disease&V& \ \ \ •·;.·.·Λν.·.·.·.νί:ίΛ;.·Α e\ \ \ 1 day ····■···· ••••■yt\ fXX X X Deterioration in healthf^-.ffi \ (Λ 8 hr - of bronchitis patients ΐ αO χ Increased deaths LU 'ratein London...... _ __ 1 hr - Change in respiratory.^^J\ and pulse rate ■"•■■■•••.'•■.•.·Λ >Λ •VvÆ-o; 5 min ° Morbidity in man • Mortality in man Δ Morbidity in animals Increased airway 30 sec A Mortality in animals resistance Taste threshold /•Odorthresnold 3 sec j ι J ι ' » ι 11 ι J Ωr L ' l l » I 1 I 111! J L 0.05 0.10 0.5 1.0 5.0 10.0
S02 concentration (ppm)
Shaded area represents the range of exposures where excess deaths have been reported. Speckled area represents the range of exposures where health effects are suspected.
Fig. 19. Health effects due to various exposures to S02. (Williamson S., 1973)
25 part Π - AIR QUALITY INDICATORS
Effects on Vegetation S0X are carried by acid deposition and are taken up by plants in two ways: directly via stornata and indirectly via soil acidification. S02 is toxic, so the plant converts it into a non-toxic or less toxic than S02 form. SOx may cause degradation of chlorophyll, reduction of the photosynthesis rate and increase of the respiration rate. Visible effects of these biochemical and physiological injuries are leaf necrosis and reduced growth. Fig. 20 illustrates the S02 level and the exposure time at which visible injuries occur. Sensitive species to S02 are: barley, pumpkin, alfalfa, cotton, wheat, lettuce, apple-tree, oats, aster, zinnias, birch, elm, white pine-tree, yellow pine-tree (Vismara R, 1988). Moreover, other woody species are reported in Fig. 21, they have been grouped according to the degree of sensitivity to S02.
WHO guidelines give the following maximum values to preserve plant life (WHO, 1987): 30 μ§ / m3 as annual average 100 μ§ / m3 as 24 h average
26 part II - AIR QUALITY INDICATORS
1 year
81 % of pine trees 1 month had no cones
4 days Premature abscission of older leaves of alfalfa 3 in o Q. Χ Acute injury to leaves o of trees and shrubs 'S 8h o TO Traces of leaf destruction in alfalfa o 1h
5min
30s
3s l ι l ι l l ι M I J L « » t » ι t I J L 0.01 0.02 0.05 0.1 0.2 0.5 1.0 2.0 Sulfur dioxide (ppm)
{ P Range of concentration· and exposure time« in which Injury to vegetation has been reported
[ ] Range of concentrations and exposure times of undetermined significance to vegetation
3 1 ppm S02 = 2.86 mg S02 / m
Fig. 20. Effects of S02 on vegetation. (VismaraR, 1988)
27 part II - AIR QUALITY INDICATORS
VERY SENSITIVE SPECIES SENSITIVE SPECIES LESS SENSITIVE SPECIES
Salix nigra Pinus nigra Populus balsamifera Ulrnus parvifolius Abies balsamea Populus canadensis Pseudotsuga menziesii 7ie americana Abies grands Pinus strobus Catalpa TMa cordata Pinus banksiana Prunus demissa Pirns contorta Populus grandidentata Popdus deltoides Platanus acerifoSa Acer negundo var. Menus Picea engelmannñ Que re us rubra Pinus ponderosa Acerspicatum Acer sacch annum Populus tremuloides Pinus resiiosa Acer saccharum Larix occidentals Tsuga heterophyia Thuja pacata Fraxinus americana Pinus montícola Thuja occidentalis Betula papyrifera Ulmus americana Picea glauca Jugtans regia Fagus silvática Platanus «pp. Ribes rubrum Carpinus betulus Alnus spp. Ribes uva-crispa Malus domestica Sy ringa vulgaris Corylus avellana Safe spp. Robinia pseudoacacia Betula spp. Prunus spp. Vitis vinifera Rhododendron spp.
Fig. 21. Relative sensitivity of woody species to S02. (Krause G.H.M., 1988)
2.2 OXIDES OF NITROGEN (NOx) AND OTHER NITROGEN COMPOUNDS
- NITROGEN OXIDES
Definition and General Concepts
Nitrogen oxides, called NOx, group the gases: nitric oxide (NO), nitrogen dioxide (N02) and dinitrogen pentoxide (N2Os). Among NOx, N02 is generally the most considered compound in environmental studies. It is a red-brown gas with a biting and choking odour. NOx are formed from atmospheric nitrogen and oxygen at high combustion temperatures. In the atmosphere they undergo complex reactions that lead to the formation of nitrous acid (HN02) and nitric acid (HN03). Then these compounds reach the Earth as acid aerosols which reach the terrestrial surface with the wet or dry depositions (acid depositions). Moreover, in the atmosphere, NOx react with OH and H02 radicals and are involved as catalysts in the production and distribution of ozone.
The level of NOx in air is a criterion for evaluating atmospheric pollution (Fig. 22). Yet, the meteorological factors also bias the urban level of NOx.
28 part II - AIR QUALITY INDICATORS
AIR QUALITY NO* (ppm)
NOT POLLUTED 0.001
POLLUTED (URBAN OR INDUSTRIAL AREAS) 0.4 - 0.5
Fig. 22. Level of NOx in unpolluted air and in polluted air.
Unit Conversion factors for N02 (WHO, 1987): 1 ppm = 1,880 μg/m3 \μ$/τη3 = 5.32 IO*4 ppm
Emission Sources NATURAL SOURCES Biological activity of soil bacteria. Volcanoes. Lightning.
MAN-MADE SOURCES Combustion of fossil fuel for energy use in domestic and industrial heating, in power plants and in motor vehicles. Industrial processes. Biomass burning. Jet aircraft.
Lifetime in the Atmosphere and Sinks Mean residence time in the atmosphere of the NOx: from some hours to 2 days (Beilke S., 1987). The primary sink is loss through wet and dry deposition.
Local Effects Damage to Construction Elements and Other Materials: fading of dyes. Visibility Reduction Photochemical Smog
Regional Effects Acid Depositions
Global Effects Depletion of Ozone Layer
29 part II - AIR QUALITY INDICATORS
Effects on Human Health For man the route of exposure to N02 is inhalation. N02 causes irritations of the respiratory tract, changing the pulmonary functions. It is known that N02 levels of 0.05 - 0.1 ppm (as average 24 h value) persisting for many months, may cause bronchitis in children. Fig. 23 reports the most important effects of nitrogen dioxide on man.
| CONCENTRATION as ppm EFFECT
less than 0.1 Olfactory threshold, some cellular effects
0.1-0.25 Impairment of dark adaptation, some epidemiological effects
0.5 Some changes in lung morphology and biochemistry
1.5 Increased airway resistance in bronchial patients
2.5 Increased airway resistance in normal individuals
13 Eye and nasal irritation
Fig. 23. Effects of nitrogen dioxide on man. (Brimblecombe P., 1986)
WHO guidelines suggest the following maximum values for N02 to protect public health (WHO, 1987): 400 μg / m3 (0.21 ppm) for an exposure time of 1 hour 150 μg / m3 (0.08 ppm) for an exposure time of 24 hours
Effects on Vegetation Acid deposition convoys NOx to vegetation. The effects of NOx on vegetation depend on the dosage and the species subject to the exposure. In fact, in scientific literature, it has been reported that low concentrations of S02 may be beneficial or negative for growth according to the species of the plant; on the other hand, a "toxicity threshold" has been demonstrated. In addition to the reduction of plant growth, the injury produces necrosis of the foliar surface. Species sensitive to NOx: azalea, sunflower, mustard, tobacco, bean (Vismara R, 1988). Moreover, synergistic effects of N02 with S02 and O3 have been proved.
30 part II - AIR QUALITY INDICATORS
WHO guidelines establish the following maximum values for N02 (WHO, 1987): <30 pg/m3 as a yearly average of 24 h means < 95 μg / m3 as a 4 h average 3 3 These values are applicable in conditions of S02 < 30 μg / m and O3 <, 60 μg / m
- NITROUS OXIDE (N20)
Definition and General Concepts Nitrous oxide does not belong to the N0X group. In the troposphere, it is an inert gas, whereas in the stratosphere it undergoes photolysis. N20 is the primary source of stratospheric NO, which plays a critical role in the control of the mass of stratospheric ozone. Moreover, it is a strong greenhouse gas with IR
Emission Sources NATURAL SOURCES Biological process of denitrification in natural soil, aquifers, oceans and estuaries.
MAN-MADE SOURCES Both fertilised and unfertilised soil, and both cultivated and uncultivated soil. Deforestation. Combustion of fossil fuel for energy use. Biomass burning.
Lifetime in the Atmosphere and Sinks Medium residence time in the atmosphere: from 120 to 150 years (Wuebbles D.J. and Edmonds J., 1991). Sinks are the stratospheric photolysis and reaction with oxygen atom.
Global Effects Depletion of Ozone Layer Greenhouse Effect
2.3 CARBON MONOXIDE AND DIOXIDE (CO,)
- CARBON MONOXIDE (CO)
Definition and General Concepts CO is an odourless and flavourless gas. It is typically produced in the incomplete combustion of carbon-containing materials; it also derives from some biological activities or industrial processes. The level of CO in air is an expression of the atmospheric pollution (Fig. 24).
31 part II - AIR QUALITY INDICATORS
In urban areas, the level of CO varies according to the traffic density. The weather conditions are another important factor influencing the concentration of CO.
AIR QUALITY CARBON MONOXIDE (ppm)
NOT POLLUTED <0.1
POLLUTED (URBAN AREA: RESIDENTIAL ZONE) 4-5
POLLUTED (URBAN AREA CENTRE OF CITY) 20-40
Fig. 24. Level of CO in unpolluted air and in polluted air.
Unit Conversion factors (WHO, 1987): 1 ppm = 1.145 mg /m3 1 mg / m3 = 0.873 ppm
Emission Sources NATURAL SOURCE Oxidation of methane and natural hydrocarbons. Plant emission. Oceans. Wildfires.
MAN-MADE SOURCE Industrial processes. Combustion of fossil fuel for energy use in domestic and industrial heating and in motor vehicles. Incinerators. Biomass burning.
Lifetime in the Atmosphere and Sinks Mean residence time in the atmosphere: ~ 0.3 years (Wuebbles D.J. and Edmonds J., 1991). In the atmosphere, CO reacts with OH and OOH radicals to finally form C02.
Effects on Human Health CO can penetrate via inhalation into human organism. CO forms strong bonds with haemoglobin to give carboxyhaemoglobin (COHb). Carboxyhaemoglobin cannot transport the oxygen to the tissues; as a result of this, hypoxia occurs. Hypoxic conditions may injure brain, blood vessels and platelets. The COHb level in non-smokers is normally around 1.2 - 1.5%; whereas in smokers it depends on the smoke and, of course, it can not be controlled apart from stopping
32 part Π - AIR QUALITY INDICATORS smoking (WHO, 1987). To prevent injury to human health, WHO has fixed the value of 2.5 - 3% as maximum COHb level. Maximum CO concentrations, in different exposure times, ensuring that the COHb level does not reach the above value, are shown in Fig. 25, as suggested by WHO guidelines. Sub-lethal effects, such as changes in behaviour and work activity, have been observed even at COHb levels about 3 - 8%; for example, a drop in attention, disturbance of the perceptive and cognitive processes and rises in reaction times to stimuli have been recorded (Vismara R, 1988). Cardiopathies and people suffering for anaemia are the most sensitive risk subjects; with COHb levels about 3%, their health begins to worsen (Vismara R, 1988).
CO CONCEIT TRATION EXPOSURE TIME mg/m3 ppm
100 100 15 minutes
60 50 30 minutes
30 25 1 hour
10 10 8 hours
Fig. 25. Maximum CO concentrations and exposure times to prevent the COHb level exceeding 2.5-3% (taken from WHO guidelines).
- CARBON DIOXIDE (C02)
Definition and General Concepts Carbon dioxide is a gas that represents the fully oxidized state of carbon. It is a normal component of air, so it is not toxic, but it has a long-term influence on the climate. In fact, C02 is a greenhouse gas which, absorbing the IR radiation, alters the radiative fluxes that determine the climate. It is not chemically interactive with other atmospheric compounds, except in the mésosphère and above where it photodissociates.
The C02 level in air is a function of the air quality, as shown in Fig. 26. It is estimated that the C02 level will increase at rate of- 0.4% yr because of anthropic activities (Wuebbles D.J. and Edmonds J., 1991).
33 part Π - AIR QUALITY INDICATORS
AIR QUALITY CARBON DIOXIDE
NOT POLLUTED 315 ppm
POLLUTED 5.67 χ 105 w 1 m3
Fig. 26. Level of C02 in unpolluted air and in polluted air.
Emission Sources NATURAL SOURCES Release from land and oceans. Biological processes of respiration and decomposition of organic matter.
MAN-MADE SOURCES Combustion of fossil fuel. Deforestation and land-use changes. Cement manufacturing.
Lifetime in the Atmosphere and Sinks Mean residence time in the atmosphere: - 200 years (Wuebbles D.J. and Edmonds J., 1991). The primary process that removes C02 from the atmosphere is the uptake of the oceans and photosynthesis in plants.
Local Effects Damage to Construction Elements and Other Materials: deterioration of stones for building (e.g. limestone).
Global Effects Greenhouse Effect Depletion of Ozone Layer
Effects on Vegetation An increase of atmospheric C02 alters the biochemical, physiological and morphological development of plants. The primary physiological processes that are affected by C02 are photosynthesis, photorespiration and stomatal conductance. This has an effect on subsequent plant responses including weight, reproduction, interactions with the environment and acclimation (Fig. 27).
34 part Π - AIR QUALITY INDICATORS
PRIMARY BIOCHEMICAL AND CELLULAR RESPONSES
Photosynthesis Photorespiration Respiration Stomatal aperture
SECONDARY BIOCHEMICAL CELLULAR AND WHOLE PLANT RESPONSES
Photosynthate translocation, concentration and composition Plant water status Tolerance to gaseous pollutants
TERTIARY WHOLE PLANT RESPONSES
Growth rate: weight, height, leaf area, node formation, senescence Growth form: height, branch and leaf number, leaf area and weight, root weight and root / shoot ratio Reproduction: flower & fruit timing, number and size, seed germination
ECOLOGICAL LEVEL RESPONSES
Plant-plant interaction: competition, interference & symbiosis Plant-animal interaction: herbivory, pollination, shelter Plant-microbe interaction: disease, decomposition S symbiosis
GENETIC RESPONSES
Genotyp« differentiation and adaptation
Fig. 27. Physiological effects of increased C02 on plant growth. (MorisonJ.I.L.,1989)
2.4 VOLATILE ORGANIC COMPOUNDS (VOCs)
Definition and General Concepts VOCs are carbon compounds (e.g. alkanes, alkenes, aromatic hydrocarbons). Depending on their origin, they can be biogenic or anthropogenic. Biogenic VOCs, e.g. isoprene and monoterpenes, are released by vegetation. Anthropogenic VOCs include most solvents, thinners, degreasers, cleaners, lubricants and liquid fuels. Some examples of common anthropogenic VOCs are the following: toluene xylene isopropyl alcohol petroleum distillates, naphthas, and mineral spirits methyl ethyl ketone (MEK) acetone paraffins olefins aromatics
35 part Π - AIR QUALITY INDICATORS
VOCs are precursors to ground-level ozone; in fact, they react photochemically with nitrogen oxides and other airborne chemicals to form ozone, which is a primary component of smog.
Emission Sources NATURAL SOURCE Swamps. Vegetation.
MAN-MADE SOURCE Transport. Domestic, agricultural and tertiary fields. Chemical process industries.
Lifetime in the Atmosphere and Sinks The atmospheric chemistry of anthropogenic and biogenic VOCs is very complex. In fact, their lifetime strictly depends on the nature of the compound and on the chemical species reacting with the VOC. As example, Figg. 28 and 29 illustrate the lifetimes of some selected VOCs with respect to their photolysis or to the degradation reactions with OH and NO3 radicals and ozone. The lifetimes have been calculated assuming specified ambient concentrations of OH and NO3 radicals and ozone, these conditions are reported below the respective figures.
Lifetine due to reaction with VOC OH O, NO, Isoprene LSbr 1.2 days Udayi Casjpbeae IS b IS days lo days 2-Careoe 13 hr 1.7 ai 36 mia i'-Cnene llar IO or Uhr d-Limoaene Uhr 1.9 hr 53 aia Myreceae 52 aun 49 asia 'Uhr Ocimeae 44 aia 43 sia 31 aia a-FheUaadrese 35 aua 13 sia t aia a-Pinese 3.4 hr 4.6 hi 10 hr 0-Piaeae 13 hr 1.1 days 44 or Sabine« 1.6 hr 4jar Uhr α-Terp ¡nene 31 mia 3 aua i ain γ-Terpiaeae UJhr IShr 24 aia Terpisolcae 49 mia 17 sua 7 min . 1,8-Cneole »dtp > 110 days Myr S-Cymeae tO divi > 330 davs 17 yr
OH 12 h daytime average concentration of 1.5 106 molecule / cm3 (0.06 ppt) NO3 12 h average concentration of 2.4 107 molecule / cm3 (1 ppt) O3 24 h average concentration of 7 1011 molecule / cm3 (30 ppb)
Fig. 28. Calculated tropospheric lifetimes of selected biogenic VOCs due to reaction with OH and NO3 radicals and ozone. (National Research Council, 1992)
36 part II - AIR QUALITY INDICATORS
Lifetime due to reaction wich voc OH NO, 0-, br Methane -12 years. > 120 years > 4,500 years Ethane 60 days > 12 years > 4,500 years Propase 13 days >25 years > 4,500 years n-Butane 6.1 days -2J years > 4,500 years π-Octane IS days 260 days >4,500 years Ethene 1.8 days 225 days 9.7 days
Propeae 7.0 hours 4.9 days 1.5 days Isoprene 1.8 hours 50 min 1.2 days o-Pinene 3.4 hours 5 min 1.0 days Acetylene 19 days a2_5 years 5.8 years Formaldehyde 1.6 days 77 days >4J years Aeetaldehyde 1.0 days 17 days >4.5 years 4 hours Acetone 68 days e >4J years 15 days Methyl ethyl 13.4 days c >
OH 12 h average concentration of 1.5 106 molecule / cm3 (0,06 ppt) NO3 12 h average concentration of 5 108 molecule / cm3 (20 ppt) O3 24 h average concentration of 7 1011 molecule / cm3 (28 ppb) c expected to be of negligible importance
Fig. 29. Calculated tropospheric lifetimes of selected anthropogenic VOCs due to photolysis and reaction with OH and NO3 radicals and ozone. (National Research Council, 1992)
Local Effects Photochemical Smog
37 part II - AIR QUALITY INDICATORS
2.5 HEAVY METALS AND THEIR COMPOUNDS
Definition and General Concepts The most important heavy metals in air quality assessment are the following: ARSENIC As CADMIUM Cd CHROMIUM Cr COPPER Cu LEAD Pb MERCURY Hg NICKEL Ni ZINC Zn
Although they can be produced by natural phenomena, most of them come from anthropogenic activities. In fact, in particular As, Cd, Cu, Ni, Pb and Zn are released with the emissions of industrial plants. Moreover it is useful to point out that gasoline, containing tetraethyllead as anti-knock, is still widely used.
Heavy metals are seriously dangerous because of their potential ecological risk of biological build-up along the food chain. In fact, heavy metals can pass upwards to the next and subsequent level of the trophic pyramid; in this way, they bioconcentrate and become more and more toxic in those animals, including man, that occupy positions at the apex.
Emission Sources NATURAL SOURCE C rust al rock and soil. Vegetation. Volcanoes. Wildfires. MAN-MADE SOURCES Industrial processes. Transport. Wastes. Combustion of wastes, fossil fuel and biomass.
Effects on Human Health Heavy metals are very toxic for man. Of course, effects depend on the heavy metals involved. For instance, the ingestion or absorption of lead over a prolonged period of time causes plumbism which is a lead poisoning characterised by colic, brain disease, anemia and inflammation of peripheral nerves. Heavy metals also may have both teratogenic and carcinogenic effects.
Effects on Vegetation Heavy metals come from the atmosphere with deposition. First, they accumulate in the canopy. Then, although some passes to the soil through litter fall, a considerable amount of heavy metals remains in the plant in the bark of the branches and stem. This accumulation leads to plant injuries which show as foliar and baric necroses.
38 part II - AIR QUALITY INDICATORS
2.6 SUSPENDED PARTICULATE
Definition and General Concepts The term Suspended Particulate (SP) indicates a mixture of organic and inorganic substances of varying size and composition which are present in atmosphere as little solid particles or volatile liquid drops The size is variable, but most particles belongs to the range 2-90 urn. The measurement of the aerodynamic diameter defines two principal categories: COARSE particles with aerodynamic diameter > 2.5 um FINE particles with aerodynamic diameter < 2.5 μιη
The composition of the SP depends on its origin. It may contain earth crostai particles, dust from cities and industries, materials produced by combustion and re-condensed vapours. The particles may include heavy metals such as lead or arsenic, heavy hydrocarbons, amianthus and other toxic compounds. The final fate of SP is the return to the soil as dry or wet deposition
The SP content in the air expresses the atmospheric pollution (Fig. 30).
AIR QUALITY SP (μιη / m3)
NOT POLLUTED AIR 10
URBAN AREA 200
HEAVILY POLLUTED AREA 2,000
Fig. 30. Content of SP in unpolluted air and in polluted air.
Emission Sources NATURAL SOURCES Volcanoes. Dust storms, such as transport of mineral particles from soil or organic particles (i.e. pollen) by means of the wind. MAN-MADE SOURCES Power plants. Industrial processes. Motor vehicles. Domestic coal burning. Industrial incinerators.
For each kind of anthropogenic sources, Fig. 31 reports the most representative pollutants that are emitted into the atmosphere as particulate.
39 part II - AIR QUALITY INDICATORS
SOURCE MOST REPRESENTATIVE GROUP
INDUSTRY heavy metals (Zn, Cd, Cu, Pb, Cr, Hg), solvents (benzene, toluene, chloralkenes, chloralkanes), PCBs
WASTE hydrocarbons, phenols, heavy metals (Cd, Cr, Ni, Pb, Zn), PCBs
TRANSPORT PAHs, hydrocarbons (ethylene, acetylene, toluene, xylene), heavy metals (Pb)
COMBUSTION hydrocarbons (pentanes, hexanes, etc.), heavy metals (V, Ni, Mn, Pb), PAHs, polychlorodibenzodioxins, polychlorodibenzofuranes
AGRICULTURE hexachlorocyclohexane, DDTs, endosulphan, chlordane, dieldrin, oxaphene, methoxychloro, heptachlorepoxide
Fig. 31. Sources of pollutants and most representative particulate bound compounds. (Mosello R et al., 1993. Translated.)
Lifetime in the Atmosphere and Sinks Suspended Particulate returns to Earth with depositions. Particles are deposited either faster or slower according to their size (Guderian R, 1986), as shown in Fig. 32.
PARTICLES DIAMETER DEPOSITION
Coarse particles > 10 urn Rapid deposition
Medium particles 0.5-10 μιη Slow deposition
Fine particles < 0.5 um Deposition velocity increases because of brownian phenomena
Fig. 32. Deposition velocity of particles as a function of their size.
Local Effects Damage to Construction Elements and Other Materials: soiling of materials for building, painted surfaces and fabrics. Visibility Reduction
40 part II - AIR QUALITY INDICATORS
Effects on Human Health SP particles are inhaled by man. They penetrate the respiratory apparatus and deposit in different tracts according to their size (from the extrathoracic tract to the respiratory bronchioles); in fact, the size of a particle influences the areas of the respiratory system which that particle is likely to affect (Fig. 33). SP causes deficits in pulmonary function and its toxicity depends on the components of the particles (i.e. lead, amianthus, heavy hydrocarbons).
Nasal /
80 -- Alveolar /" \ ι \ Pulmonary Ι Λ Ι \ Ι \ - ι / t ? 60 ι / ι ι / t ι / | Ι / ι s Ι / ι ι / ι 40 - / / \ •ν ^-._ ^ ' ι /
20 -
Traeheo-bronchiil
I ι ι I τ » ι W 0.01 ο.ο: 0.05 0.1 0.2 0.5 i.O 2.0 Panicle radius Cum)
Fig. 33. Fractional amount of particles of various size deposited in the different areas of the respiratory tract. (Brimblecombe P., 1986)
Effects on Vegetation The particles can be separated into inert and toxic. Inert particulate causes mainly physical effects on plants, whereas toxic particulate have both chemical and physiological effects depending on the toxicity of the components that constitute the particles.
41 part II - AIR QUALITY INDICATORS
2.7 CHLOROFLUOROCARBONS (CFCs)
Definition and General Concepts The term chlorofluorocarbons refers to a family of compounds derived from methane or higher carbon-content hydrocarbon molecules. A CFC forms by replacing all hydrogen atoms with chlorine or fluorine halogens. When bromine is used, the compounds are called halons. CFCs are liquid or gaseous products. They are used as aerosol spray propellants, refrigerants, solvents and plastic foaming agents. They accumulate in the atmosphere. In stratosphere, they react, with catalytic effect, to form highly reactive chlorine species which can electronically react with the ozone destroying it. The catalytic effect means that just one CFC molecule can destroy 20,000 - 30,000 molecules of 03 (Vismara R, 1988). For this reason, CFCs are involved in the depletion of the ozone layer. Fig. 34 shows the destruction mechanism of the stratospheric ozone because of the release of CF2CI2 in the environment.
CF2Cl2 + hv >- CI + CF;CI 50km 280 K Ozone absorbs UV light O3 + CI ► CIO + 02 0 · 7torr θ' + CIO ► CI + O-, CI + CH4 net O + Oy>O2 + 02
CF,Ch release HCL S,ratosPh">W^down Oo Troposphere ^»300n rrr, 'Rain- '0-l5km Ra,rT 210K 70torr mmmmsp 5LV
Fig. 34. Destruction mechanism of the stratospheric ozone following the release of CF2Cl2 in the environment. (SamiullahY, 1990)
Because CFCs are strong absorbers of ER, they contribute to the greenhouse effect when they are in the lower atmosphere. In coming years, it is expected that production and emission of CFCs will be reduced as a result of the Montreal Protocol (Council Decision 88/540/EEC) and other international
42 part II - AIR QUALITY INDICATORS
policy agreements. For example, the Council Regulation EEC/594/91 reported the estimated ozone-depleting potentials for the CFCs and other compounds which are recognised to be substances that deplete the ozone layer (Fig. 35).
Emission Sources NATURAL SOURCES None.
MAN-MADE SOURCE Chemical industry: refrigeration and air conditioning, closed-cell and open-cell foams, aerosol propellant.
Lifetime in the Atmosphere and Sinks Mean residence time in the atmosphere (Wuebbles D.J. and Edmonds J., 1991): CFCI3 (CFC-11) from 50 to 80 years CF2C12 (CFC-12) from HOto 130 years CFC12CF2C1 (CFC-113) ~0 years CF2C1CF3 (CFC-115) ~ 400 years
In the troposphere there are no significant losses; whereas in the stratosphere, CFCs photodissociate and react with oxygen atoms forming reactive chlorine compounds.
Global Effects Depletion of Ozone Layer Greenhouse Effect
Ozone-depleting Croup Substance potential
Croup 1 CFdj (CFC-11) LO CF2C32 (CFC-12) LB C2F5CI3 (CFC-113) 0» CiNCIj (CFC-I IO u> C2i'$a (CFC-1 IS) 0.Í Croup II CT3C1 (CFC-13) ID (CFC-111) ID c2ra5 C2F2CI4 (CFC-112) 1.0 C3FCI7 (CFC-211) LO CiFtOí (CFC-212) LO . C&Øi (CFC-213) U) C5F4CI4 (CFC-214) LO C3F5C13 (CFC-21S) LO Cír^Crí CFC-216) LO cjira (CFC-217) IJO continued
43 part II - AIR QUALITY INDICATORS
Oionc-dcpleiing Croup Substance potential Croup ill Cf2UrCI (halon-1211) 3.0 CKjür Chalón· 1301) 10.0 C2F4UT2 (halon-2402) 6.0
Croup IV ecu (carbon tetrachloride) 1.1
Croup V C2H3CI32 (1,1,1 -1 r ich 1 oroe iha ne) 0.1
Croup VI CHFCI2 CHCFC-2I) CHF2a (HCFC-22) CH2FO (HCTC-31) C2HFCI4 (HCKM21) C2HF2CIJ (HCFC-122)
C2HF3a2 CHOC-123) C2HF4CI CHC1-C-124) C2H2FÛ3 (HCFC-131) Croup VI C2II2H2CI2 (HCFC-132) C2I fr^a (IICFC-133) C2I13F02 (IICI:C-141> Ç2H3F2CI (l ICFC-142) C2I14FO (wcrc-151) f C3IIF06 (na c-22i) c^in^as (Iia:C-222) C3IIF3CL4 (HafC-223) C^UMC^ QICFC-224) C311F5CI2 (IICFC-225) C31 ιΐ'όα (1 ICTC-226)
C3ii2Fa5 (IICFC-231) C3ll2ls2CM (lia-C-232) C3H2lf3Cl3 (lia-C-233) C3H2F4CI2 (I1C1-C-234) C3II2I-5O (IICFC-235) C3II3FCI4 (HCFC-241)
c3i 131-203 (HCIC-242) C3II3H3CI2 (UOC-243) C3II3IMCI (na-c-244) C3H4FCI3 •(MO-C-25I) C3lHI!2d2 (na-C-252) C3lUI'3a (uac-253) C3H5102 (IIŒC-26D C3H5l'2a (liaC-262) ' C3II6IO 0lQ"C-27n .. ·;..
Fig. 35. Substances that deplete the ozone layer. (Council Regulation EEC/594/91)
44 part Π - AIR QUALITY INDICATORS
2.8 CARCINOGENIC SUBSTANCES
Definition and General Concepts "Carcinogenic substances" means all those substances and preparations which has been proved to possess carcinogenic properties via the air. PAHs are the most representative group. They are organic compounds with two or more benzene rings. There are many PAHs, of which the best known is benzo[a]pyrene. They derive from incomplete combustion of organic materials and from evaporation in gasoline- powered motors. Because of this, the PAH concentration in urban centres is 1,000 times greater than that measured in wooded areas. Some PAHs, deriving from combustion, which are recognised to be carcinogenic are: benzo[a]pyrene 3 -met hy I cholant hr ene dibenzo[c,g]carbazole benzo[cb]fluoranthene benzo[c]phenananthrene
Emission Sources NATURAL SOURCE Wildfires. MAN-MADE SOURCES Combustion of wastes, fossil fuel, biomass. Motor vehicles.
Effects on Human Health PAHs irritate eyes and interfere with the respiratory processes. It is recognised that PAHs are carcinogenic.
2.9 OZONE (03)
Definition and General Concepts Ozone is a blue gas with a typical odour of garlic. It is a reactive oxidant gas which is, in the atmosphere, created and destroyed at the same time. In fact, it forms from 02 and atomic oxygen (produced by solar photodissociation of N02) and is simultaneously demolished by reaction with atomic oxygen or stratospheric NOx-components and by photodissociation. Because these two processes are in photochemical equilibrium, the ozone concentration remains stationary. This equilibrium can be disturbed by some anthropogenic gases such as CFCs. In the stratosphere, where most ozone is found, it has a crucial role because it adsorbs the UV radiation (0.2 - 0.3 um) emitted by the sun, which damages plant and animal life. It is noticed that a significant weakening of the stratospheric ozone layer could lead to the increase of instances of skin cancer in the human population.
45 part II - AIR QUALITY INDICATORS
On the other hand, in the troposphere, high concentrations of ozone may be harmful for man, animals and plants. Besides, because the tropospheric ozone is a greenhouse gas which can trap the radiation emitted by the earth, it is reasonable to suppose that an increase of the tropospheric ozone concentration could contribute to a warming of the terrestrial surface. It is for this reason that ozone is supposed to be involved in "global change", where global change means changes in climate and changes in atmospheric chemistry.
Unit Conversion factor (WHO, 1987): 1 ppm = 2 mg / m3
Emission Sources NATURAL SOURCE Atmospheric processes.
MAN-MADE SOURCES Indirectly by chemical reactions of gaseous emissions of plants (in fact, 03 is a secondary pollutant).
Lifetime in the Atmosphere and Sinks Mean residence time in the atmosphere: ~ 1 week (Beilke S., 1987). Sinks are the losses due to chemical reactions with atmospheric compounds and to deposition on earth.
Local Effects Damage to Construction Elements and Other Materials: see Fig. 36. Photochemical Smog
MATERIAL ATTACKED DAMAGE
RUBBER and ELASTOMERS weakening and breaking
NATURAL and SYNTHETIC FABRICS weakening
DYES fading
Fig. 36. Effects of ozone on some materials. (Vismara R, 1988. Translated and modified.)
46 part II - AIR QUALITY INDICATORS
Global Effects Greenhouse Effect
Effects on Human Health Exposure to 03 may cause a decrease in pulmonary function, irritation to eyes, nose and throat. Asthmatic crises, in predisposed subjects, have also been reported. Irritation to sense organs has been noted in subjects exposed to concentrations around 0.1 - 0.15 ppm (Vismara R, 1988).
To protect public health, WHO guidelines suggest the following maximum values for 03 (WHO, 1987): from 150 to 200 μg / m3 (from 0.076 to 0.1 ppm) for an exposure time of 1 hour from 100 to 120 μg / m3 (from 0.05 to 0.06 ppm) for an exposure time of 8 hours
Effects on Vegetation Vegetation absorbs ozone via the stornata by the gas exchange process. These visible injuries have been observed: premature senescence and defoliation, leaf- yellowing, necrosis. Some metabolic processes are also damaged; in fact, it has been noted that the rate of photosynthesis may decrease. The presence of S02 increases the negative effect of O3 on the leaves. Species sensitive to ozone are: alfalfa, barley, bean, oats, onion, maize, apple-tree, vine, tobacco, tomato, spinach, poplar, maple, white pine-tree, yellow pine-tree (Vismara R, 1988). Moreover, Fig. 37 lists other woody species grouped according to their degree of sensitivity to ozone.
WHO guidelines report the following maximum values for O3 in order to protect vegetation (WHO, 1987): 200 μg / m3 for an exposure time of 1 hour 65 pg / m3 for an exposure time of 24 hour 60 pg / m3 during the growing season ( 100 days)
47 part Π - AIR QUALITY INDICATORS
VERY SENSITIVE SPECIES SENSITIVE SPECIES LESS SENSITIVE SPECIES
Ailanthus altissima Acernegundo Abies concolor Cotoneaster divaricatus Forsythia χ intermedia Acer platonoides Cotonea ster horìzontalis 'Lynwood Gold' Bet ula pendula Gleditsia triacanthos inermis Larix kaempferi Buxus sempervirens Juglans regia Ligustrum vulgare Fagus sylvatica Larix decidua Liquidambar styraciflua Ilex aquifolium Ligustrum velgare var. pyramidae Philadelphus coronarius Ilex crenata Liriodendron tulipifera Pinus strobus Juglans nigra Pinus nigra Pinus sylvestris Picea abies Platanus occidentalis Sy ringa vulgaris Picea pungens Populus maximowiczii χ trichocarpa Tsuga canadensis Pieries japónica Sorbus aucuparia Pseudotsuga menziesii Spiraea χ vanhouttei Quercus robur Symphoricarpos albus Quercus rubra Robinia pseudoacacia Sophora Japónica Thuja occidentalis Tilia americana Tilia cordata Viburnum χ burkwoodii Viburnum cariesii
Fig. 37. Relative sensitivity of woody species to ozone. (Krause G.H.M., 1988)
48 part ΠΙ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES
3 INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES
The reference values for air quality indicators have been defined by means of legislation and guidelines. This chapter has therefore been divided into two different sections: Regulations and Guidelines. The former reports the reference values taken from EU Directives and Italian legislation. The latter uses WHO guidelines to draw out the indicator reference values.
3.1 REGULATIONS
European Union regulations have here been considered as the starting point; then, the Italian legislation has been examined, to see how Italy has applied the EU Directives. As already mentioned in section 1.2.7, two different series of laws have been produced: the former concerns air quality monitoring and the later concerns the control of pollutant emissions. For this reason, two parts have been separated: Air Quality and Emissions from Industrial Plants.
3.1.1 AIR QUALITY
The following regulations refer to the safeguard of air quality. With this aim, they fix reference values, as Limit Values and Guide Values, for air pollutants.
The first EU Directive produced to protect air quality is Directive 80/779/EEC. It establishes the Guide Values and Limit Values for sulphur dioxide and suspended particulate in the atmosphere (Figg. 38, 39,40,41 and 42).
REFERENCE PERIOD GUIDE VALUE FOR SULPHUR DIOXIDE
Year 40 to 60 arithmetic mean of daily mean values taken throughout the year
24 hours 100 to 150 daily mean value
Fig. 38. Guide Values for sulphur dioxide expressed in pg / m3. (Directive 80/779/EEC)
49 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES
REFERENCE PERIOD GUIDE VALUE FOR SUSPENDED PARTICULATE
40 to 60 Year arithmetic mean of daily mean values taken throughout the year
24 hours 100 to 150 daily mean value
Fig. 39. Guide Values for suspended particulate (measured by black-smoke method) expressed in μg / m3. (Directive 80/779/EEC)
REFERENCE PERIOD LIMIT VALUE FOR SUSPENDED PARTICULATE
80 Year median of daily mean values taken throughout the year
Winter 130 (1 October to 31 March) median of daily mean values taken throughout the winter
Year 250 (·) (made up of units of 98th percentile of all daily mean values measuring periods of 24 hours) taken throughout the year
(*) this value must not be exceeded for more than three consecutive days
Fig. 40. Limit Values for suspended particulate (measured by black-smoke method) expressed in pg / m3. (Directive 80/779/EEC)
50 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES
REFERENCE PERIOD LIMIT VALUE FOR ASSOCIATED VALUE FOR SULPHUR DIOXIDE SUSPENDED PARTICULATE
80 >40 median of daily mean values median of daily mean values Year taken throughout the year taken throughout the year (made up of units of measuring periods of 24 hours) 120 ¿40 median of daily mean values median of daily mean values taken throughout the year taken throughout the year
130 >60 median of daily mean values median of daily mean values taken throughout the winter taken throughout the winter Winter (1 October to 31 March) 180 ¿60 median of daily mean values median of daily mean values taken throughout the winter taken throughout the winter
250 (*) >150 98th percentile of all daily mean 98th percentile of all daily mean Year values taken throughout the year values taken throughout the year (made up of units of measuring periods of 24 hours) 350 (*) ¿150 98th percentile of all daily mean 98th percentile of all daily mean values taken throughout the year values taken throughout the year
(*) this value must not be exceeded for more than three consecutive days
Fig. 41. Limit Values for sulphur dioxide with the associated values for suspended particulate (measured by black-smoke method) expressed in pg / m3. (Directive 80/779/EEC)
51 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES
j REFERENCE PERIOD LIMIT VALUE FOR ASSOCIATED VALUE FOR SULPHUR DIOXIDE SUSPENDED PARTICULATE
80 >150 median of daily mean values median of daily mean values taken throughout the year taken throughout the year Year
120 ¿150 median of daily mean values median of daily mean values taken throughout the year taken throughout the year
130 >200 median of daily mean values median of daily mean values taken throughout the winter taken throughout the winter j Winter (1 October to 31 March) 180 ¿200 meciian of daily mean values median of daily mean values taken throughout the winter taken throughout the winter
250 (*) >350 98 (*) this value must not be exceeded for more than three consecutive days Fig. 42. Limit Values for sulphur dioxide with the associated values for suspended particulate (measured by gravimetric method) expressed in pg / m3. (Directive 80/779/EEC) Regarding heavy metals, Directive 82/884/EEC fixes a Limit Value for lead in the air specifically in order to help protect human beings against the effects of lead in the environment. This value is the following: 3 LIMIT VALUE OF LEAD IN AIR 2 pg / m expressed as annual mean concentration The Italian legislation complied to the EU Directives on air quality. In fact, DPCM No. 30, 28/03/1983 has established the maximum limits of acceptability of the concentrations and maximum exposure limits for air pollutants in the outside environment (Fig. 43). Besides, this decree also gives the Limit Value of the concentration in the air of 52 part lil - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES hydrocarbons because it is known that they are the precursors of the pollutants considered in Fig. 43 (Fig. 44). POLLUTANT LIMIT VALUE Median of the average 24 h concentration levels 80 μς / m3 recorded throughout the entire year SULPHUR DIOXIDE expressed as SO, 98th percentile of the average 24 h concentration levels 250 ug / m3 recorded throughout the entire year NITROGEN DIOXIDE Average 1 h concentration level not to be exceeded 200 ug / m3 expressed as NO, more than once a day OZONE Average 1 h concentration level not to be reached 200 μg / m3 expressed as O, more than once a month Average 8 h concentration level 10 mg/m3 CARBON MONOXIDE expressed as CO Average 1 h concentration level 40 mg / m3 LEAD Arithmetical average of the average 24 h concentration 2 μg / m3 levels recorded over 1 year Average 24 h concentration level 20 ug / m3 FLUORINE Average of the average 24 h concentration levels 10μg/m3 recorded over 1 month Arithmetical average of all the average 24 h 150μg/m3 concentration levels recorded over a year SUSPENDED PARTICULATE 95th percentile of all the average 24 h concentration 300 μς / m3 levels recorded over a year Fig. 43. Limit Value of acceptability of the concentrations and maximum exposure limits for air pollutants outside. (DPCM No. 30, 28/03/1983. Translated.) 53 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES CONDITIONS FOR PRECURSOR LIMIT VALUE THE LIMIT VALUE TO BE VALID Average consecutive 3 h concentration levels during To be adopted only in TOTAL HYDROCARBONS periods of the day to be 200 ug / m3 areas and periods of the excluding methane specified according to the year when the limit values expressed as C various different areas by the for ozone have been appropriate regional significantly exceeded authorities Fig. 44. Limit Value of the concentrations in air of precursors of the pollutants shown in Fig. 43, to adopt in certain conditions. (DPCM No. 30, 28/03/1983. Translated.) Directive 85/203/EEC furnishes the air quality standards for nitrogen dioxide as Limit Value and Guide Value (Figg. 45 and 46). REFERENCE PERIOD LIMIT VALUE FOR NITROGEN DIOXIDE 200 Year 98th percentile calculated from the mean values per hour or period of less than an hour recorded throughout the year Fig. 45. Limit Value for nitrogen dioxide expressed in pg / m3. (Directive 85/203/EEC) REFERENCE PERIOD GUIDE VALUE FOR NITROGEN DIOXIDE 50 50th percentile calculated from the mean values per hour or per period of less than an hour recorded throughout the year Year 135 98th percentile calculated from the mean values per hour or per period of less than an hour recorded throughout the year Fig. 46. Guide Values for nitrogen dioxide expressed in pg / m3. (Directive 85/203/EEC) 54 part ΠΙ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES In Italy DPR No. 203, 24/05/1988 was produced with the purpose of implementing EU Directives No. 80/779, 82/884, 84/360 and 85/203. It determines the Guide Values for sulphur dioxide, nitrogen dioxide and suspended particulate and the Limit Values for sulphur dioxide and nitrogen dioxide (Figg. 47 and 48). POLLUTANT GUIDE VALUE REFERENCE PERIOD Arithmetical average of the average 24 h concentration levels recorded over 1 year: 01-04/31-03 from 40 to 60 μ9 / m3 \ SULPHUR DIOXIDE SO, Average 24 h value: 0 a.m. /12 p.m. from 100 to 150 μς / m3 of every day 50th percentile of the average 1 h concentration levels recorded throughout the entire year 01-01/31-12 50 ug / m3 NITROGEN DIOXIDE NO, 98th percentile of the average 1 h concentration levels recorded throughout the entire year 01-01/31-12 135μg/m3 Arithmetical average of the average 24 h concentration levels recorded over 1 year 01-04/31-03 SUSPENDED from 40 to 60 μg equivalent black smoke / m3 PARTICULATE (measured by the black-smoke method) Average 24 h value: 0 a.m. /24 p.m. from 100 to 150 μg equivalent black smoke / m3 of every day Fig. 47. Guide Values of sulphur dioxide, nitrogen dioxide and suspended particulate for air quality. (DPR No. 203, 24/05/1988. Translated.) 55 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES POLLUTANT UMIT VALUE REFERENCE PERIOD Median of the average 24 h concentration levels recorded throughout the entire year: 01-04/31-03 80 μg / m3 ', SULPHUR DIOXIDE 98th percentile of the average 24 h concentration SO, levels recorded throughout the entire year 01-04/31-03 250 ug / m3 Median of the average concentration levels recorded during the winter: 01-10/31-03 130pg/m3 ! NITROGEN DIOXIDE 98th percentile of the average 1 h concentration NO, levels recorded throughout the entire year 01-01/31-12 200 μg / m3 Fig. 48. Limit Values of sulphur dioxide and nitrogen dioxide for air quality. (DPR No. 203, 24/05/1988. Translated.) The aim of DMA 12/11/1992 is to control atmospheric pollution in large urban zones. This decree fixes the limits of the Attention Level and Alarm Level for atmospheric pollutants (Fig. 49). The attention level and alarm level define the concentration of the pollutant which determines the Attention State and Alarm State respectively. The attention state is a situation that, if persisting, leads to the alarm state. In turn, the alarm state, if persisting, leads to potential exceeding of the maximum limits of acceptability (fixed by DPCM No. 30, 28/03/1983), which is risky for the general population. 56 part ΠΙ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES POLLUTANT ATTENTION LEVEL ALARM LEVEL SULPHUR DIOXIDE ug / m3 125 Π 250 C) (daily average) TOTAL SUSPENDED PARTICLES ug/m3 90 (*) 180 (*) (daily average) 3 NITROGEN DIOXIDE ug / m 200 400 (average 1 h value) CARBON MONOXIDE mg / m3 15 30 (average 1 h value) OZONE ug/m3 120 240 (average 1 h value) (*) jointly in the same monitoring station Fig. 49. Attention levels and alarm levels for air pollutants in large urban zones. (DMA 12/11/1992. Translated.) The still temporary Directive 92/72/EEC closes the regulations concerning the air quality monitoring. It establishes the thresholds for ozone concentrations in the air according to four specific purposes (Fig. 50). PURPOSES THRESHOLDS FOR OZONE CONCENTRATIONS HEALTH PROTECTION 100 ug / m3 for the mean value over 8 hours VEGETATION PROTECTION 200 ug / m3 for the mean value over 1 hour 65 pg / m3 for the mean value over 24 hours POPULATION INFORMATION 180 ug / m3 for the mean value over 1 hour POPULATION WARNING 360 ug / m3 for the mean value over 1 hour Fig. 50. Thresholds for ozone concentrations in the air. (Directive 92/72/EEC) 57 part ΠΙ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES 3.1.2 EMISSIONS FROM INDUSTRIAL PLANTS Six categories of industrial plants were considered in Directive 84/360/EEC, they are the following: (1) ENERGY INDUSTRY • Coke ovens • Oil refineries (excluding undertakings manufacturing only lubricants from crude oil) • Coal gasification and liquefaction plants • Thermal power stations (excluding nuclear power stations) and other combustion installations with a nominal heat output of more than 50 MW (2) PRODUCTION AND PROCESSING OF METALS • Roasting and sintering plants with a capacity of more than 1,000 tonnes of metal ore per year • Integrated plants for the production of pig iron and crude steel • Ferrous metal foundries having melting installations with a total capacity of over 5 tonnes • Plants for the production and melting of non-metals having a total capacity of over 1 tonne for heavy metals or 0.5 tonne for light metals (3) MANUFACTURE OF NON-METALLIC MINERAL PRODUCTS • Plants for the production of cement and rotary kiln lime production • Plants for the production and processing of asbestos and manufacture of asbestos- based products • Plants for the manufacture of glass fibre or mineral fibre • Plants for the production of glass (ordinary and special) with a capacity of more than 5,000 tonnes per year • Plants for the manufacture of coarse ceramics notably refractory bricks, stoneware pipes, facing and floor bricks and roof tiles (4) CHEMICAL INDUSTRY • Chemical plants for the production of olefins, derivatives of olefins, monomers and polymers • Chemical plants for the manufacture of other organic intermediate products • Plants for the manufacture of basic inorganic chemicals (5) WASTE DISPOSAL • Plants for the disposal of toxic and dangerous waste by incineration • Plants for the treatment by incineration of other solid and liquid waste (6) OTHER INDUSTRIES • Plants for the manufacture of paper pulp by chemical methods with a production capacity of 25,000 tonnes or more per year 58 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES Following this directive, Directive 88/609/EEC was produced. It must be applied to existing and new combustion plants with a thermal input equal or greater than 50 MW independent of the type of fuel. Regarding new plants, this directive establishes the limits of the emission of sulphur dioxide, nitrogen oxides and dust according to the type of fuel used (Figg. 51, 52, 53, 54 and 55). SOLID FUELS 200 - 100 200 300 400 500 600 MWth Fig. 51. Sulphur dioxide emission limit values for new plants which use solid fuel. (Directive 88/609/EEC) TYPE OF FUEL LIMIT VALUES (mg / Nm*) Gaseous fuels in general 35 Liquefied gas 5 Low calorific gases from gasification of refinery residues, 800 coke oven gas, blast-furnace gas Fig. 52. Sulphur dioxide emission limit values for new plants which use gaseous fuel. (Directive 88/609/EEC) 59 part ΙΠ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES 3 mg S02/ Nm 1700 I LIQUID FUELS 1600 1500 1400 1300 1200 1100 1000 900 800 700 eoo 500 400 1 1 1 1 ι ι t^JLmn 100 200 300 400 500 600 MWth Fig. 53. Sulphur dioxide emission limit values for new plants which use liquid fuel. (Directive 88/609/EEC) TYPE OF FUEL LIMIT VALUES (mg / Nm*) Solid in general 650 Solid with less than 10% volatile compounds 1,300 Liquid 450 Gaseous 350 Fig. 54. Nitrogen oxides emission limit values for new plants according to the type of fuel used. (Directive 88/609/EEC) 60 part ΠΙ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES TYPE OF FUEL THERMAL CAPACITY EMISSION LIMIT VALUES (MWth) (mg / Nm3) ¿500 50 Solid ¿500 100 Liquid (*) all plants 50 5 as rule Gaseous all plants 10 for blast furnace gas 50 for gases produced by the steel industry, which can be used elsewhere (*) a limit value of 100 mg / Nm3 may be applied to plants with a capacity of less than 500 MWth burning liquid fuel with an ash content of more than 0.06% Fig. 55. Dust emission limit values for new plants according to the type of fuel used. (Directive 88/609/EEC) In Italy, Directive 88/609/EEC was implemented in the two decrees DMA 08/05/1989 and DMA 12/07/1990. The former concerns new large combustion plants, whereas the latter concerns existing industrial plants. Because this paper is focused on the EIA, only the aspect relative to new plants is subject of this work, therefore only DMA 08/05/1989 has been examined. This decree reports the emission limit values for sulphur dioxide, nitrogen oxides and dust according to the type of fuel used (Fig. 56, 57, 58, 59, 60,61 and 62). 61 part ΙΠ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES 3 mg S02/Nm SOLID FUELS 100 200 300 400 500 600 MWth Fig. 56. Sulphur dioxide emission limit values for new plants which use solid fuel. (DMA 08/05/1989) m g SO, /Nm3 1700 i LIQUID FUELS 1000 1S00 — \ 1400 \ 1300 \ 1200 \ 1100 \ 1000 \ 900 — \ soo — \ 700 — \ «00 — \ soo \ 100 200 300 400 S00 • 00 MWth Fig. 57. Sulphur dioxide emission limit values for new plants which use liquid fuel. (DMA 08/05/1989) 62 part ΠΙ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES TYPE OF FUEL LIMIT VALUE (mg / Nm3) Gaseous fuels in general 35 Liquefied gas 5 Low calorific gases from gasification of refinery residue, 800 coke oven gas, blast-furnace gas Fig. 58. Sulphur dioxide emission limit values for new plants which use gaseous fuel. (DMA 08/05/1989. Translated.) mgMO./NmΪΠ»Γ 600 SOUD FUELS 500 400 300 200 100 1 1 , 1 1 1 1 1 1 1 1 100 200 300 400 500 600 MWth Fig. 59. Nitrogen oxides emission limit values for new plants which use solid fuel. (DMA 08/05/1989) 63 part ΙΠ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES 3 mgNOx/Nm UQUID FUELS 500 400 — 300 200 100 _l L 1_ .!_. 1 t 1 ■ ■ » ' 100 200 300 400 500 600 MWth Fig. 60. Nitrogen oxides emission limit values for new plants which use liquid fuel. (DMA 08/05/1989) 3 mg NOx / Nm 400 — GASEOUS FUELS 300 — — 200 ^~ 100 — 1 1 1 J ' ■ ' IIII 100 20O 300 400 500 600 MWth Fig. 61. Nitrogen oxides emission limit values for new plants which use gaseous fuel. (DMA 08/05/1989) 64 part IH - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES TYPE OF FUEL THERMAL CAPACITY LIMIT VALUE (MWth) (mg / Nm3) liquid and solid ¿50 50 5 as a rule gaseous ¿50 10 for blast furnace gas 50 for gases produced by the steel industry which can be used elsewhere Fig. 62. Dust emission limit values for new plants according to the type of fuel used. (DMA 08/05/1989. Translated.) Directive 89/369/EEC concerns new municipal waste incineration plants. The air pollutants considered are dust, heavy metals, hydrochloric acid, hydrofluoric acid and sulphur dioxide. For each of these pollutants, the emission limit values are specified according to the nominal capacity of the plant (Fig. 63). POLLUTANT less than 1 tonne / h 1 tonne / h or more but 3 tonnes / h or more less than 3 tonne* / h Total dust 200 100 30 Heavy metals: - Pb + Cr + Cu + Mn - 5 5 -Ni +As 1 1 - Cd and Hg 0.2 0.2 Hydrochloric acid (HCl) 250 100 50 Hydrofluoric acid (HF) - 4 2 Sulphur dioxide (SO,) - 300 300 Fig. 63. Emission limit values for dust, heavy metals, hydrochloric acid, hydrofluoric acid and sulphur dioxide (expressed in mg / Nm3) as a function of the nominal capacity of the incineration plant. (Directive 89/369/EEC) 65 part III - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES 3.2 GUIDELINES WHO guidelines have defined reference values for the most crucial air pollutants (WHO, 1987). These guidelines are the result of experimental observations of the damage to the environment due to the exposure to atmospheric pollutants. The reference values reported represent the pollutant level, combined with the relative exposure time, at which no adverse effects are expected. In particular, the maximum concentration of pollutant that seems not to be a danger for man and plants has been evaluated; so two sections have been separated: Human Health and Vegetation. The guidelines for preserving human health have been located in the former, whereas the latter contains the guidelines for protecting plant life. The reference values, reported below, have already been given for each pollutant in PART II under the points Effects on Human Health and Effects on Vegetation. They also have been summarised here in tables to give a whole overview. 3.2.1 HUMAN HEALTH To protect human health from air pollution, WHO has suggested guideline values for some air pollutants (WHO, 1987). These values are indicated as maximum concentration level of pollutant with exposure time. They are summarised in Fig. 64. 3.2.2 VEGETATION WHO also has drawn up guidelines for the protection of vegetation (WHO, 1987). Like the guidelines to protect human health given below, these values express the maximum concentration level of pollutant joined with the exposure time. They are summed up in Fig. 65. 66 part UI - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES POLLUTANT REFERENCE VALUE EXPOSURE TIME 500 ug / m3 10 minutes SULPHUR 350 μ9 / m3 1h DIOXIDE SO, 125μg/m3 (1) 24 h 50μg/m3 (1) 1 year NITROGEN 400 μg / m3 (0.21 ppm) 1 h DIOXIDE NO, 150 μ9 / m3 (0.08 ppm) 24 h 100 mg/m3 15 minutes CARBON 60 mg / m3 (50 ppm) 30 minutes MONOXIDE CO 30 mg/m3 (25 ppm) 1h 10 mg / m3 (10 ppm) 8h 125μg/m3 (1) (2) 24 h SUSPENDED PARTICULATE 50 ug/m3 (1) (2) 1 year from 150 to 200 μς / m3 (from 0.076 to 0.1 ppm) 1 h OZONE from 100 to 120 μ9 / m3 (from 0.05 to 0.06 ppm) 8h (1) considered jointly (2) measured by the black-smoke method Fig. 64. Air quality WHO guidelines to protect human health. 67 part ΙΠ - INDICATOR REFERENCE VALUES ACCORDING TO REGULATIONS AND GUIDELINES POLLUTANT REFERENCE VALUE EXPOSURE TIME 30 μρ / m3 1 year SULPHUR Annual average DIOXIDE SO, 100 ug/m3 24 h 24 h average 30w/m3 (*) 1 year NITROGEN Yearly average of 24 h means DIOXIDE NO, 95rø/m3 (*) 4h 4 h average 200 ug/m3 1h OZONE 65 ug / m3 24 h 60 μg 1 m3 growing season (100 day) ■ ■-■■ (*) in conditions of SO2 < 30 pg / m3 and O3 < 60 pg / m3 Fig. 65. Air quality WHO guidelines to protect vegetation. 68 REFERENCES REFERENCES LEGISLATION AND GUIDELINES COUNCIL DECISION 88/540/EEC. Council Decision of 14 October 1988 concerning the conclusion of the "Vienna Convention for the protection of the ozone layer and the Montreal Protocol on substances that deplete the ozone layer. Official Journal of the European Communities L 297, 30-10-1988: 8-28. COUNCIL REGULATION EEC/594/91. Council Regulation of 4 March 1991 on substances that deplete the ozone layer. Official journal of the European Communities L 67, 14- 03-1991:1-10. DIRECTIVE 80/779/EEC. Council Directive of 15 July 1980 on air quality limit values and guide values for sulphur dioxide and suspended particulates. Official Journal of the European Communities L 229, 30-08-1980: 30-48. DIRECTIVE 82/884/EEC. Council Directive of 3 December 1982 on a limit value for lead in the air. Official Journal ofthe European Communities L378, 31-12-1982: 15-19. DIRECTIVE 84/360/EEC. Council Directive of 28 June 1984 on the combating of air pollution from industrial plants. Official Journal of the European Communities L 188, 16-07-1984: 20-25. DIRECTTVE 85/203/EEC. Council Directive of 7 March 1985 on air quality standards for nitrogen dioxide. Official Journal of the European Communities L 87,27-03-1985: 1-7. DIRECTIVE 85/337/EEC. Council Directive of 27 June 1985 on the assessment of the effects of certain public and private projects on the environment. 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Criteri generali per la prevenzione dell'inquinamento atmosferico nelle grandi zone urbane e disposizioni per il miglioramento della qualità dell'aria (General criteria preventing atmospheric pollution in large urban zones and provisions for the improving of air quality). Gazzetta Ufficiale della Repubblica Italiana No. 272, 18-11- 1992: 15-29. DPCM No. 30, 28/03/1983. Limiti massimi di accettabilità delle concentrazioni e di esposizione relativi ad inquinanti dell'aria nell'ambiente estemo (Maximum limit values of acceptability of the concentrations and exposure for air pollutants outside). Supplemento Ordinario della Gazzetta Ufficiale della Repubblica Italiana No. 145, 28-05-1983: 3- 21. DPCM No. 377,10/08/1988. Regolamentazione delle pronunce di compatibilità ambientale di cui all'art. 6 della legge 8 luglio 1986, n. 349, recante istituzione del Ministero dell'ambiente e norme in materia di danno ambientale (Regulation of the pronouncements of environmental compatibility within the meaning of art. 6 of the law of 8 July 1986, No. 349, recent institution of the Ministry of the Environment and rules concerning environmental damage). Gazzetta Ufficiale della Repubblica Italiana No. 204, 31-08- 1988:6-11. DPCM 27/12/1988. Norme tecniche per la redazione degli studi di impatto ambientale e la formulazione del giudizio di compatibilità ambientale di cui all'art. 6 della legge 8 luglio 1986, n. 349, adottate ai sensi dell'art. 3 del decreto del Presidente del Consiglio dei Ministri 10 agosto 1988, n. 377 (Technical rules for the drawing up of environmental impact studies and the formulation of the judgement of environmental compatibility within the meaning of art. 6 of the law of 8 July 1986, No. 349, adopted in conformity with the art. 3 of the Decree of the President of the Council of Ministers, 10 August 1988, No. 377). Gazzetta Ufficiale della Repubblica Italiana No. 4, 05-01-1989: 17-37. DPR No. 203,24/05/1988. 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(Ed), Acid Precipitation Series - Vol. 5, Teasley J.I. (Series Ed), Butterworth Publishers: 51-63. GISOTTI G. and BRUSCHI S. 1990. Valutare l'ambiente (Evaluate the environment). La Nuova Italia Scientifica, Rome, 467 pp. GUDERIANR. 1986. Terrestrial ecosystems: particulate deposition. In "'Air pollutants and their effects on the terrestrial ecosystem", Legge AH. and Krupa S.V. (Eds), Vol. 18, Wiley Series in Advances in Environmental Science and Technology, Nriagu J.O. (Series Ed), Wiley-Interscience Publication: 339-363. KRAUSE G.H.M. 1988. Impact of air pollutants on above-ground plant parts of forest trees. In "Air pollution and ecosystems", Mathy P.(Ed), D. Reidel Publishing Company: 168-216. LEGGE AH. and KRUPA S.V. 1986. Air pollutants and their effects on the terrestrial ecosystem, Legge AH. and Krupa S.V. (Eds), Vol. 18, Wiley Series in Advances in Environmental Science and Technology, Nriagu J.O. 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Technical Note No. 1.93.157 ISEI/IE/25 82/93, 143 pp. 73 ABBREVIATIONS AND ACRONYMS ABBREVIATIONS AND ACRONYMS The following abbreviations and acronyms have been used throughout this paper: CFC ChloroFluoroCarbon DDTs Dichloro-Diphenyl-Trichloroethanes DMA Decreto del Ministero dell'Ambiente (Decree of the Minister of the Environment) DMS dimethylsulphide DPCM Decreto del Presidente del Consiglio dei Ministri (Decree of the President of the Council of Ministers) DPR Decreto del Presidente della Repubblica (Decree by the President of the Republic) Ed Editor EC European Community eg- for example EIA Environmental Impact Assessment etc. etcetera EU European Union Fig. Figure h hour i.e. that is IR infrared solar radiation °K degrees Kelvin km kilometre MEK Methyl Ethyl Ketone No. number PAHs Polycyclic Aromatic Hydrocarbons PAN peroxyacetyl nitrate PCBs Polychlorinated Biphenyls ppb parts per billion ppm parts per million ppt parts per trillion SP Suspended Particulate UV ultraviolet solar radiation VOC Volatile Organic Compound WHO World Health Organization yr year 74 HOW TO INTERACT WITH THE JRC? 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