ENVIRONMENTAL MONITORING Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin TRANSBOUNDARY AIR POLLUTION Franco DiGiovanni and Philip...
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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

TRANSBOUNDARY AIR POLLUTION Franco DiGiovanni and Philip Fellin Airzone One Ltd., 222 Matheson Boulevard East, Mississauga Ontario, Canada Keywords: Long range transport, acid precipitation, acid deposition, arctic haze, persistent organic pollutants, smog, ozone, visibility, mercury, particulate matter Contents

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1. Introduction 2. Background on the atmosphere and dynamics 3. Smog 4. Acid Deposition 5. Particulate Matter 6. Mercury 7. Haze 8. Persistent Organic Pollutants Glossary Bibliography Biographical Sketches To cite this chapter Summary

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A broad range of pollutants have been described that share the common phenomena of transboundary transport. It has been seen that transboundary transport occurs either because the pollutants have very low deposition velocities (as in the case of Arctic haze constituents or fine particulate matter (PM)), or an extended period of time is required for the pollutant to develop from the precursor compounds (smog, acid rain) or are chemically inert (mercury) or go through a multi-hop pathway as in the case of persistent organic pollutants (POPs). In general, the smog and acid rain issues have had the longest history of study and are generally better understood. More recently issues of POPs and mercury have come to the fore, and research is in early development, possibly because their effects are more insidious. There are two major challenges with transboundary pollutants. The first is the international co-operation required to deal with them. Fortunately, in recent years, the political climate has become more attune to international co-operation to alleviate transboundary air pollution (e.g., North American Free Trade Association – Commission of Environmental Co-operation, rationalization of EU environmental regulations, UN CLRTAP). Other factors aide these political decisions, which must balance social and economic considerations against environmental, such as the recognition of co-benefits of emissions reductions where certain pollutants have multiple effects (e.g. NOx in acid rain and smog issues).

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

The second challenge involves providing the appropriate data upon which reduction decisions can be made. These data are generated by the scientific monitoring and modeling investigations described in this paper. For transboundary pollutant problems, the need to co-ordinate international networks of monitoring stations has been successfully met in Europe (EMEP) and in North America (Environment Canada 1998) and modeling efforts have often been coordinated, although to a greater extent in Europe under the EMEP Program than in North America. Given the complexity of the vertical and horizontal structure of the atmosphere, and the large range of scales atmospheric motion affecting transboundary air pollution, the types of complex modeling efforts require are perhaps best accomplished by international co-operation.

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1. Introduction Pollutants emitted from natural or anthropogenic sources to the atmosphere may be advected over distances of several to hundreds of meters (micro-scale), 1000’s of meters to hundreds of kilometers (meso-scale) or hundreds to 1000’s of kilometers (macro-scale) (Oke 1978). The upper end of macro-scale dispersal describes global dispersal patterns and is also referred to as ultra-long range transport. When airborne contaminants cross geopolitical boundaries or migrate across several geographic zones, the pollution is designated as transboundary even if the physical distance of the boundary from the emitting pollutant source is quite short.

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Many transboundary issues trace their origin to releases from specific sources impinging directly upon receptors in other jurisdictions. For example, a smelter in Trail, British Columbia, released SO2 from a tall stack that impinged directly on sites in Washington State, USA, under specific atmospheric conditions. This issue was the subject of protracted negotiations from the 1930s to the 1950s when it was resolved by treaty negotiated through the International Joint Commission (IJC). The “Superstack” in Sudbury, Ontario, a 335 m chimney erected to disperse SO2 emissions from a nickel smelter in the late 1960s, became the single largest source of SO2 emissions in North America, initially at about 5 000 Tonnes/annum (currently reduced to less than 500 Tonnes/annum). Emissions were tracked as far as lower New York State in the USA. Many more examples are available from all over the world of transboundary pollution problems of this type. Over the last thirty years or so, however, transboundary air pollution has become synonymous with broader, more complex issues incorporating contributions from many sources and vast regions, complex atmospheric processes and multiple chronic effects on receptors that are more difficult to detect and define unambiguously. The latter view of transboundary air pollution is discussed in this article drawing upon research experiences and regulatory and environmental issues in North America, similar work in Europe and broader international efforts including the United Nations Environment Program. In this paper we begin with a brief overview of atmospheric processes that affect air pollution transport. The rest of the paper will describe the major transboundary pollutants. Specifically, we will describe their sources, aspects of their long-range transportation, and their deposition or incorporation into the ecosystem.

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

Appropriate reduction strategies require knowledge of the emissions, dispersal and deposition processes, as well as an understanding of atmospheric processes and use of that knowledge to identify significant sources. This knowledge and data is gained by monitoring of atmospheric pollutants, often utilizing networks of monitoring stations, and computer-based models of atmospheric dispersal and chemical processes that allow prediction of the affects of suggested reduction methods. Such models require monitoring data for validation, and thus monitoring and modeling studies are often conducted in parallel.

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To effectively manage a transboundary pollution issue, the source-receptor relationship is an important one to elucidate. In other words, it is important to know how much deposition at location “y” occurs as a result of emissions from location “x” and, moreover, to understand if a linear or non-linear relationship exists between source emissions and receptor deposition. Both these factors are crucial to applying appropriate controls, and are especially important considerations in transboundary transport where an appreciable disjoint may develop between variations in the pollution emission and variations in atmospheric concentrations of the pollutants at the receptor. It is the relationship between emissions and final deposition of the pollutant that computer models attempt to simulate. Successful simulations allow the models to be used in a predictive mode to assess the success of various proposed reduction strategies. Accordingly, the last two sections of each pollutant description will describe examples of investigative techniques and reduction strategies that may have been implemented or are planned. 2. Background on the Atmosphere and Dynamics

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When natural or anthropogenic pollutants are emitted from their source, air currents carry the pollutants, dilute them, and expose them to varying environmental conditions or other chemicals in the atmosphere, before the pollutants are either chemically transformed or deposited to the earth’s surface (land or water) through dry or wet deposition processes. Therefore, it is essential to understand the atmospheric structure and dynamics that control these air movements. A description is given based upon issues relevant to long-range transport. 2.1. Vertical Structure of the Earth’s Atmosphere

The vertical structure of the earth’s atmosphere is classified by the thermal gradient. The bottom layer, where the air temperature generally decreases with increasing altitude, is known as the troposphere. The height of the troposphere varies from approximately 16 km over the Tropics to approximately 9 km over the Polar region. Above the troposphere, between approximately 12 and 50 km, the stratospheric layer contains much of the ozone that protects the earth from sun’s UV radiation. Within the troposphere, the vertical structure is further sub-divided into the surface layer, the planetary boundary layer (PBL) and the free atmosphere. It is within the PBL that most of the “weather,” that affects pollutant transformation and dispersal, occurs. The surface layer is defined as the layer with approximately constant shear stress (a measure of the drag of the earth’s surface on the atmosphere) with increasing

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

height where the winds are determined by the nature of the surface and vertical gradients of temperature. This layer may extend from 50 - 100 m above the earth’s surface. The rest of the planetary boundary layer extends up to approximately 500 – 3000 m and is a region of transition wherein shear stresses are variable and winds are determined by horizontal pressure gradients, Coriolis and surface friction forces and also vertical temperature gradients. The variation of forces with increasing height causes wind directions to vary as height increases. Above the planetary boundary layer, the balance of the troposphere is made up by a region called the free atmosphere where air motions are governed by the horizontal (synoptic) pressure gradients and the Coriolis force and flow is quite laminar with winds of a high velocity.

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The top of the boundary layer is marked by a temperature inversion, that is, a layer above which environmental temperatures increase. Such a “capping” inversion usually traps pollutants released at the earth’s surface within the boundary layer since vertical movements are subdued. Turbulence and convective activity within the PBL causes pollutants to be mixed within this layer. Because the height of the PBL varies, and especially is lower at night, highly buoyant pollutants, released from an industrial smoke stack, for example, or from other elevated point sources may penetrate the inversion and invade the free atmosphere where the potential for long-distance dispersal is greatly enhanced. Also, pollutants released into the nocturnal boundary layer (NBL) can result in elevated atmospheric concentrations because there is less depth available for dilution of the pollutant. The interested reader is directed to Stull (1997) and Lutgens and Tarbuck (1986) for further details. 2.2. Horizontal Structure of the Earth’s Atmosphere

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Wind flow over the earth’s surface is affected by phenomena of varying length and time scales. Pollutants released into the atmosphere, and which take part in transboundary pollution, are influenced by motions covering virtually the entire spectrum of atmospheric motions. At the larger scales, the influences are controlled by large scale global circulation patterns, and at the smaller scales by small scale turbulence and air viscosity effects. Air masses on the earth’s surface have distinct characteristics of temperature and humidity derived from the characteristics of the surface over which it resides. As a result, meteorologists have classified air masses according to their sources region. Thus the Arctic air mass has characteristics derived from the Arctic region, the Polar air mass is characteristic of temperate regions and the Tropical air mass has climatic features typical of the Tropics. The general circulation over the earth is such that warmer air from the topics moves towards the poles and cold air from the poles moves towards the equator. The flow patterns are modified by the rotation of the earth, and the three-cell meridional circulation system attributed to Rossby. Flows patterns are illustrated in Figure 1. The north-south limits of each of the cells mark the general boundary between the three air masses. However, these boundaries vary seasonally. For example, the Arctic front moves south in northern winter and north in the northern summer. These movements are important factors affecting phenomena such as the Arctic haze and

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persistent organic pollutant (POPs) influx into the Arctic region as will be described later.

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Figure 1. A schematic representation of Rossby’s three-cell meridional scheme (adapted from Lutgens and Tarbuck 1986)

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In addition, the boundaries between air masses are usually wave-like in nature, with the waves referred to as Rossby waves. These large scale, or planetary, waves, ultimately spawn low pressure systems, or cyclones, which bring clouds and precipitation. In North America, cyclogenesis predominantly occurs in the lee (east) of the Rocky Mountains and along the east coast of North America, and generally propagate to the east and northeast (Figure 2). Cyclones are also centers of air convergence and result in vertical movements of air. Cyclone development and movement of the cyclone centre obviously modifies airflow and has a fundamental affect on pollutant transport as well as deposition. Superimposed upon the large-scale air movements, micro-scale dispersal also occurs with time and length scales in the order of hours and kilometers, respectively. The relatively constant wind speeds and direction within the PBL, over these length and time scales, allows simplifying assumptions to be made about the physics of atmospheric dispersal that greatly ease mathematical modeling of air flow and have prompted the development of numerous dispersal models. In the main, these are based on Eulerian or Lagrangian modeling principles and on our understanding of the

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momentum or pollutant flux relationships within the surface layer and of wind speed variations within the rest of the boundary layer (Arya 1988, Blackadar 1997, Stull 1997).

Figure 2. Climatological summary of cyclone tracks over north America (solid lines represent extratropical cyclones and dashed lines denote cyclones, adapted from Irving 1991) 2.3. Pollutant Deposition

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During transport, pollutants may undergo chemical transformation, or depletion from the atmosphere by transfer to the earth’s surface by one of two basic mechanisms; wet deposition, wherein pollutants are absorbed by rain, snow or fog and deposited on to the earth’s surface (precipitation scavenging), and dry deposition, wherein the pollutants fall or are absorbed at the earth’s surface by soil, water or vegetation directly. (i) Precipitation Scavenging

Particles: As water drops fall through the air they collide with pollutant particles and collect them. The efficiency with which rain drops collect particles is a function of the radii of the rain drops and particles and the fall speed of the rain drop (assuming the pollutant particles have negligible vertical velocity). Integration over the size range of rain drops and pollutant particles, together with data on rainfall rates, yields the total amount of particulate matter that a rain event can collect and transfer to the earth (Seinfeld 1986). Gases: The capture of particles is assumed to be irreversible; however, gas capture by water drops may be irreversibly or reversibly captured. The scavenging rate of an irreversibly soluble gas is determined by the equilibrium constant between the gasphase and aqueous phase of the gas, as well as factors such as the droplet size, fall velocity, concentration of the gas and height of droplet fall (Seinfeld 1986). However,

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

the capture rate of a reversibly absorbed gas is determined by the aqueous concentration of the pollutant gas within the droplet as well as the scavenged gas’ vapor pressure close to the surface of the drop. Thus, the point of drop saturation must be known or calculated to determine scavenging rate and may vary with drop and environmental conditions (Seinfeld 1986). (ii) Dry Deposition Dry deposition of gases or particles is a complex process which is normally conceptualized as being analogous to electrical or heat transfer, and occurring in three consecutive steps:

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1. the aerodynamic component, wherein substances are transferred from the atmosphere to the deposition surface, and is largely controlled by atmospheric turbulence and stability, 2. the surface component, wherein substances are transferred through the laminar sub-layer surrounding objects, which is largely controlled by molecular diffusivity, and, 3. the transfer component, wherein substances are absorbed by the surface, and which is controlled by species solubility and/or absorptivity. Although the laminar sub-layer surrounding objects (plant leaves, soil surface, etc.) may be quite thin (10-1 to 10-2 cm thick), it is often a crucial step in the entire transfer process. The strength of dry deposition is represented by the deposition velocity, vd (units of velocity), which is a constant of proportionality between the atmospheric flux to the surface and the concentration of a particular pollutant at some reference height. The three components of dry deposition are combined in the form of resistances, thus

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vd = (ra + rs + rt )-1

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where ra is the aerodynamic resistance, rs is the surface resistance and rt is the transfer resistance. These components are often derived theoretically or experimentally and readers are referred to various articles (e.g., Brook et al. 1999) and texts (e.g., Seinfeld 1986) for further description. With these concepts firmly in mind it is now useful to describe specific “pollutionbased” issues that are of concern and that can be attributed, at least in part, to transboundary movements of pollutants. 3. Smog 3.1. Introduction Smog is one of most well known pollutants among the general public. It occurs mainly in urban or built-up areas and causes reduced visibility and can make breathing difficult, even for healthy people, and can also increase susceptibility to cardiorespiratory diseases (Burnett et al. 1995). Smog is a complex mix of pollutants

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

including nitrogen oxides (NOx), sulfur dioxide (SO2), volatile organic compounds (VOCs), particulate matter (PM) and ozone (O3), but can also contain many other compounds. Smog issues first came to light during the famous smoke and fog (thus “smog”) episodes in London during 1952 for which over 4000 deaths are attributed (Wark et al. 1998), although most smog problems today are produced by photochemical oxidants.

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Ground-level (as opposed to Stratospheric) ozone is a colorless and highly irritating gas that forms just above the earth's surface. It is called a "secondary" pollutant because it is produced when primary pollutants undergo reactions due to photochemically induced production of free radicals. Two primary pollutants that strongly affect ground-level ozone are NOx and VOCs. NOx includes the gases nitric oxide (NO) and nitrogen dioxide (NO2), and are produced mostly by burning fossil fuels. Ozone not only affects human health, it can damage vegetation and decrease the productivity of some crops, injure flowers and shrubs and may contribute to forest decline (e.g., in Western Europe [Lubkert et al. 1984]) and can also cause collateral damage to manmade materials (Seinfeld 1986). Fine particulates also cause health problems that are described more fully in a later section. 3.2. Emissions and Transport

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Smog tends to be a regional pollutant, as opposed to a global problem. An example of a transboundary smog problem occurs in southern Ontario, Canada. About half of the nitrogen oxides and VOCs that form smog in southern Ontario originate in the United States Midwest and are carried by prevailing winds through the Ohio Valley (www.ec.gc.ca) to the north-east. But as with other transboundary pollutants, local sources are also important. In Ontario, the largest single domestic source of smog is vehicle emissions; about 40 per cent of ozone-forming nitrogen oxides come from this source. Long-range transport of peroxyacetyl nitrate (PAN, another smog constituent) and ozone were also reported in northern Europe (Hov 1984, Hov et al. 1986, Brice et al. 1984). The atmospheric residence time of these pollutants is approximately of the order of the breakdown time for the anticyclonic PBL in the mid-latitudes (2-5 days). In this length of time, the pollutants disperse over geopolitical boundaries in Europe and North America. Nitrogen oxides and VOCs are also emitted by many industrial processes, including refining and power generation. Solvents and coatings used in industrial processes produce smog-forming VOC emissions, as do many cleaning products, paints, pesticides and fertilizers that contain solvents. In addition, volatile organic compounds (VOCs) are given off naturally by some vegetation especially broad leaf trees (Finlayson-Pitts and Pitts 1986). Fine particles are emitted directly into the air from many sources such as combustion sources (forest fires, internal combustion engine emissions, power plants, etc.). They are also formed in the atmosphere from the chemical reaction of gaseous pollutants,

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

and are thus called ‘secondary’ particles. Fine particle sources are described more fully later. Human activities are responsible for the increases in ground-level ozone in recent years. About 95 per cent of nitrogen oxides from human activity come from the burning of coal, gas and oil in motor vehicles, homes, industries and power plants. 3.3. Investigation Methods

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(i) Monitoring Networks of monitoring sites across North America measure the constituents or indicators of urban and regional smog. Canada maintains two air-monitoring networks which are involved in measuring smog constituents. The National Air Pollution Surveillance (NAPS) Network is primarily an urban network, gathering measurements on ozone, PM, SO2, CO, NOx and VOCs, with 239 air monitoring stations across the country. The Canadian Air and Precipitation Monitoring Network (CAPMoN), mentioned also in the acid deposition section, is a rural network with 10 air monitoring stations in Canada and one in the USA. CAPMoN locations are chosen to ensure measurements are regionally representative and unaffected by local sources of air pollution and so data from CAPMoN are used to assess transboundary transport of pollutants.

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In the U.S., the EPA's ambient air quality monitoring program includes measurement of smog and smog precursors and is carried out by State and local agencies. The program consists of three major categories of monitoring networks that measure the criteria pollutants (including ozone and PM); State and Local Air Monitoring Stations (SLAMS), National Air Monitoring Stations (NAMS), and Special Purpose Monitoring Stations (SPMS). Additionally, a fourth category of a monitoring station, the Photochemical Assessment Monitoring Stations (PAMS), which measure ozone precursors (approximately 60 volatile hydrocarbons and carbonyls) have been established under the 1990 Amendments to the US Clean Air Act (Figure 3). In Europe, the EMEP program (Co-operative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe, e.g., United Nations 1991) (www.emep.int) is a co-operative program for monitoring and evaluation of the long range transmission of air pollutants in Europe, and includes assessing the transboundary transport of photo-oxidants. In addition, the formation of acidifying species is included and, more recently, also persistent organic pollutants (POPs) and heavy metals. (ii) Modeling Modeling of smog transport and chemistry has had a relatively long history in North America. In the US, much developmental work has culminated in the regulatory application of photochemical models. In particular, the US EPA has developed, and promotes the use of, the Urban Airshed Model (UAM, Environmental Protection Agency 1990). UAM is an urban scale, three dimensional, grid-type numerical simulation model. The model incorporates a condensed photo-chemical kinetics

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

mechanism for urban atmospheres. The UAM is designed for computing O3 concentrations under short-term, episodic conditions lasting one or two days resulting from emissions of NOX and VOCs. Models-3 is an environmental modeling system developed by the US EPA to simulate smog development and transport, among other pollutants. The initial version of Models-3 contains a Community Multiscale Air Quality (CMAQ) modeling system for urban to regional scale air quality simulation of tropospheric ozone, acid deposition, visibility and fine particulate matter. The target grid resolutions and domain sizes for CMAQ range spatially and temporally over several orders of magnitude.

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In Europe, the EMEP program utilizes both Eulerian and Lagrangian modeling techniques.

Figure 3. Locations of Photochemical Assessment Monitoring Network in the USA non-attainment areas. (http://www.epa.gov/air/oaqps/pams/pamsfig2.pdf) 3.4. Reduction Actions

Within Canada, as with other airborne pollutants, provincial environment ministries use regulations, standards and approvals to limit industrial emissions of many pollutants, including smog precursors. Voluntary measures by industry, such as the adoption of codes and management practices, are also utilized. A coalition of government, business and other organizations has developed smog reduction plans aimed at lowering emissions of nitrogen oxides and VOCs by 45% of 1990 levels by the year 2015 (Ontario Ministry of the Environment 1998) in regions affected such as southern Ontario. Similar actions are also being taken in the lower Fraser Valley (Vancouver) and the Atlantic region. Other provincial initiatives include mandatory

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vehicle inspection programs in Ontario (“Drive Clean”) and British Columbia, highway patrols which issues warnings and fines to drivers of visibly polluting vehicles, updating air quality standards and air monitoring networks, and establishing an interim air quality criterion for fine PM. At the federal level, mandatory emissions reporting for many substances, including smog precursors, has been established and continually expands in terms of number of substances reported and lowering reporting thresholds (Canada’s National Pollutant Release Inventory web-site). Additional resources have been added to Canada’s air pollutant monitoring networks and, in 1997, Canada initiated the first program on smog forecasting in eastern Canada.

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In June 2000, the federal government of Canada, the provinces and the territories, except Quebec, adopted new Canada-Wide Standards (CWS) for PM and Ozone. To meet its commitments under the CWS, resources have been allocated to implement a NOx emission limit on the fossil fuelled electricity sector in Ontario and Quebec; and reductions have been mandated for other emissions such as VOCs from a range of products including paints and paint coatings, degreasing agents, solvents, printing chemicals and cleaners.

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On December 7, 2000, an agreement to reduce transboundary smog was signed between Canada and the U. S. through the Ozone Annex under the 1991 Canada-U.S. Air Quality Agreement. North American government agencies are also devoting resources for modeling of transboundary flows and regional smog formation and transport. Work is also being done to conduct regional risk analyses to characterize major sources of smog in selected regions such as ozone non-attainment areas to prepare for the next round of Ozone Annex negotiations in 2004. Similar issues exist in Europe also, and are being handled in a similar manner through the European Union.

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The severest regional smog problems exist in many of the large conurbations (large metropolitan areas with populations greater than 10,000,000) in the developing world where vehicle populations are large, emissions regulations are either non-existent or poorly enforced and environmental conditions are conducive to the production of urban smog. Mexico City (Mexico), Rio DeJaneiro and Sao Paolo (Brazil), Santiago (Chile), Caracas (Venezuela), Calcutta and New Delhi (India), Bankok (Thailand), Jakarta (Indonesia), and Lagos (Nigeria) are among the megacities (as well as most of southern China) identified with the most significant smog problems (Faiz et al 1990). 4. Acid Deposition 4.1. Introduction

When SO2 and NOx are released into the atmosphere (from combustion sources or from ore smelting, for example) these compounds are oxidized to the produce acidic compounds sulfuric and nitric acid respectively:

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

SO2+NOx+H2O+ O2 + oxidants → acidic compounds Most of the atmospheric acidic species are rain scavenged and brought to earth via precipitation causing “acid rain.” Because there may be other causes of acidity in precipitation such as naturally occurring weak organic acids (where pH ≈ 5.6 for “nonacidic” rain in equilibrium with CO2 in air), acid rain is defined as being precipitation with pH of less than 5.0 (Seinfeld 1986). The effects of increased acidic deposition to soil, plants and water bodies has been extensively documented in North America (e.g., Irving 1991) and in Europe (Overrein 1972, Overrein et al. 1980). 4.2. Emissions and Transport

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In North America, predominant sources of SO2 are in the USA in states to the south of Lake Erie (Figure 4) with effects felt in north-eastern USA and in south-eastern Canada. In 1995, the estimated transboundary flow of SO2 from the USA to Canada was between 3.5 – 4.2 millions of tonnes per year (Meteorological Service of Canada web-site http://www.ec.gc.ca/acidrain/acidrainfact.html). Studies by the Canadian Meteorological Service indicate that some regions in eastern Canada received deposition amounts in excess of the target loading of 20 kg ha-1 yr-1 for SO42- wet deposition (target loading = loading above which significant ecological effects are encountered). For both SO2 and NOx, studies in eastern Canada also indicate that those regions receive a disproportionate amount of sulfate and nitrate deposition compared to local emissions (Environment Canada 1997a). NOx sources include the transportation sector and industrial combustion sources. In Canada, the transportation sector accounts for 60% of NOx emissions (www.ec.gc.ca).

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Both SO2 and NOx compounds are also emitted naturally. Natural sources of sulfur, eventually forming acidic species, are predominantly water bodies (seas, lakes, etc.). Overall, biogenic sources of sulfur are a minor constituent of acidic sulfur in the atmosphere in North America. In Ontario, for example, biogenic sources are thought to contribute approximately 5-8% to ambient excess SO42-, but may be significant locally (Environment Canada 1997a) and especially so for other parts of the earth. In terms of biogenic emissions, the primary NOx species, NO, is released as a result of bacterial activity in the upper few centimeters of soil (Finlayson-Pitts and Pitts 1986). Emissions (for SO2) and acid precipitation effects across North America are illustrated in Figure 4. Despite the popular term “rain,” a significant portion of the acidic species that are adsorbed by the earth’s surface may be deposited via dry deposition (Brook et al. 1999) and also by fog, especially at higher elevations (Environment Canada 1997a). Dry deposition has been found to be especially important for nitrate deposition (Environment Canada 1997a). Because of a number of factors (location and height of release of the precursor chemicals, rate of chemical reaction, etc.) acid deposition effects can be measured many thousands of kilometers from the source region, making this pollutant a transboundary issue both in Europe and in North America. The

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

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pathways by which these acidic species are formed, transported and deposited are shown in Figure 5.

Figure 4. Sulfur dioxide emissions in North America in 1980 and precipitationweighted mean pH in 1980 (adapted from Seinfeld 1986).

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4.3. Investigative Methods

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(i) Monitoring

Acid deposition and airborne concentration of species is monitored by well established networks of samplers. In Canada, the national network is called CAPMoN (Canadian Air and Precipitation Monitoring Network). This network is operated by the Meteorological Service of Canada in order to study the regional patterns and trends of acid rain, air and precipitation chemistry. CAPMoN measures wet deposition (rain or snow) and (inferential) dry deposition, as well as the ambient concentrations of acid forming gases and particles. Inferential dry deposition estimates are obtained by modeling vd and using that estimate, together with measured concentrations, to estimate fluxes to the earth’s surface (e.g., Brooks et al. 1997a). The network began operating in mid-1983. Currently, there are 10 air and precipitation CAPMoN sites across Canada. In the USA, the National Atmospheric Deposition Program (NADP) and the Clean Air Status and Trends Network (CASTNet) were developed to monitor wet and dry acid deposition, respectively. CASTNet was established in 1991 to measure various air

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

pollutants including those involved in acid deposition. CASTNet estimates dry deposition inferentially using the Multi-Layer Model (Myers et al. 1998). In 1998 CASTNet included measurements of precipitation chemistry, ozone concentrations, aerosols and visibility-related parameters at 79 primarily rural sites.

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In Europe, the EMEP program includes measurement of ambient and precipitated acidifying species.

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Figure 5. Atmospheric paths leading to acid deposition (adapted from Seinfeld 1986).

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(ii) Modeling

Numerous models have been developed over the years to investigate acidic deposition. Models have been developed that include both the physical transport of the precursor species as well as including effects of dry and wet deposition in order to determine source-receptor relationships. In Canada, two different long-range transport and transformation models have been used by the federal government to investigate acid deposition issues. The first is the LRTAP model (Environment Canada 1997a) which is a one-and-a-half layer Lagrangian model with linear chemistry and monthdependent process parameterization coefficients. This model has been used in the investigation of acid rain issues in several studies, including (i) transboundary flux of acidifying species in Alberta, Canada (Environment Canada 1997a), (ii) to help locate monitoring stations for the CAPMoN program in appropriate locations, and also, (iii) to estimate the effects of control legislation in Canada and the USA (Environment Canada 1997b). In addition, the Canadian government has also developed the Integrated Assessment Model (Environment Canada 1997a), which links transport

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

models, such as LRTAP, with emissions and effects models to assess control and damage costs (Environment Canada 1997a). The second model is the Acid Deposition and Oxidant Model (ADOM, Venkatram et al. 1988) which was also developed, in part, by the Canadian government, and is an Eulerian model with (more realistic) non-linear chemical transformation modeling. A similar Eulerian model has also been developed by USA agencies; the Regional Acid Deposition Model (RADM, Chang et al. 1987). These two models have been compared during validation field tests (Environment Canada 1997a).

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Transboundary fluxes in Europe and import/export budgets for oxidized sulfur (SOx), NOx and reduced nitrogen (NHx) are computed with the EMEP Eulerian Acid Deposition Model. Transboundary fluxes are also available for years from 1985 through 1996 computed with the EMEP Lagrangian Acid Deposition Model (see EMEP web-site, www.emep.int and Tsyro 1998a, b). 4.4. Reduction Actions

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In Canada new regulations were initiated in 1985 as part of the Eastern Canada Acid Rain Program which committed Canada to cap SO2 emissions in the seven provinces from Manitoba eastward at 2.3 million tonnes by 1994, a 40% reduction from 1980 levels. By 1994, all seven provinces had achieved or exceeded their targets. In 1997, emissions in eastern Canada totalled just 1.75 million tonnes — 24% below the 2.3million tonne cap and a 54% reduction from 1980 levels (Environment Canada 1998). The Federal government has signed the Canada-Wide Acid Rain Strategy for Post2000, and is currently working in collaboration with the provinces and territories on its implementation. The Strategy calls for new emission reduction targets in eastern Canada, pursuing emission reduction commitments from the USA, ensuring the adequacy of acid rain science and monitoring, and minimizing growth in emissions. In addition, the government of Canada is reducing sulfur in gasoline through regulations that require reductions across Canada to 150 parts per million (ppm) by 2002 and 30 ppm starting in 2005 (Environment Canada 1998). Moreover, the Canadian government has announced its intention to further reduce sulfur in diesel to 15 ppm by 2006 in line with similar requirements for diesel sold in the United States. So far, Canadian NOX emissions have declined slightly, from 2.1 million tonnes in 1990 to 2.0 million tonnes in 1995. This is largely a result of industrial process changes, retrofitting of fossil-fuelled power plants, and provincial and federal programs targeting mobile sources (Environment Canada 1998). Internationally, under Article V of the Canada-U.S. Air Quality Agreement, Canada and the USA are obligated to notify the each other of any proposed actions, activities or projects which, if carried out, would be likely to cause significant transboundary air pollution. The US EPA's Acid Rain Program limits, or "caps," SO2 emissions from power plants at 8.95 million tons annually and allows those plants to trade SO2 allowances. Interested readers are directed to the US EPA web-site for the most up-to-date information.

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5. Particulate Matter 5.1. Introduction Issues of particulate matter (PM) as an air pollutant are also mentioned as part of the discussion on Arctic haze and smog issues. However, it can also constitute a health issue by itself.

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Airborne particles cover a range of sizes, from the sub-micron to sizes of the order of 100 μm (1/10th of a millimeter). However, from a human health point of view, the particles of greatest concern are those inhaled. Because of the physics of particle flow and deposition, only those particles with an aerodynamic diameter (Reist 1984) less than 10 μm (PM10), or “fine” PM, enter the respiratory system and those less than 2.5 micrometers in size (PM2.5, a “sub-set” of PM10) are responsible for causing the greatest harm to human health. PM10 particles generally affect the upper respiratory system and PM2.5 can be inhaled deep into the lungs reaching areas where the lung cells replenish the blood with oxygen. Breathing problems, respiratory symptoms, irritation, inflammation and damage to the lungs and premature deaths have been attributed to fine PM. However, many of these attributions are based on populationbased statistical (epidemiological) studies and there are some disputations over the linkages between outdoor ambient fine PM and health effects (Vedal 1997). Nonetheless, governments in north America have proceeded with establishing air quality standards for PM10 and PM2.5. 5.2. Emission and Transport

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Some PM2.5 are released directly to the atmosphere from industrial smokestacks and automobile tailpipes, but a large percentage are formed in the atmosphere from other pollutants such as SO2, NOx and VOCs producing secondary particulates. Sources of these other pollutants have been mentioned in other sections. These compounds tend to combine to form particles under particular atmospheric conditions (Seinfeld 1986). While some of the PM10 are generated naturally by sea salt spray, wind and wave erosion, volcanic dust, windblown soil and micro-organisms, they are also produced by human activities, such as construction, demolition, mining, road dust, tire wear and grinding processes of soil, rocks, or metals. Many of the sources, especially the natural sources of fine PM, are not well characterized (Ontario Ministry of the Environment 1999). In particular, primary bioaerosols (micro-organisms, e.g., pollen and fungal spores) have been recognized as health threat for a number of years (see journals Grana and Aerobiologia), but linkages to the PM issue were not made until recently (e.g., Stieb et al. 2000). Because secondary aerosols can be produced over a period of several days, and because fine PM in general has low dry deposition velocities, dispersal must be considered over regional scales, and to a lesser degree, over continental scales making transport of this pollutant a transboundary issue. Locally, high concentrations can occur over urban areas due to primary particulate and precursor gas emissions over the area.

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5.3. Investigation Methods (i) Monitoring

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Networks of samplers for PM10 are relatively well established in North America. In Canada, the NAPS network, mentioned in an earlier section, provides data on PM10 and PM2.5 (e.g., Brook et al. 1997b). Within the Province of Ontario, the provincial Ministry of the Environment has installed 23 TEOM (Tapered Element Oscillating Microbalance) samplers to provide continuous, hourly measurements of PM10. In the U.S., the EPA monitors progress of the individual States in meeting air quality standards by measuring concentrations of criteria pollutants. The U.S. Clean Air Act requires every State to establish a network of air monitoring stations for these pollutants (including PM10), using criteria set by the EPA for their location and operation (previously mentioned SLAMS network). Each State must provide the US EPA with an annual summary of monitoring results at each SLAMS monitor. This information is summarized in the Aerometric Information Retrieval System (AIRS) available at the EPA web-site. In addition, PM data is collected by the US IMPROVE network (Beveridge 1999) established primarily to investigate haze issues. In Europe, The EMEP network was expanded to include PM measurements as a result of international assessments of health risks imposed by transboundary PM dispersal (e.g., WHO-EMEP 1999). (ii) Modeling

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Primary PM can, and has, been modeled using many of the mesoscale dispersal models currently in use, since it requires only considerations of passive dispersal. On the other hand, secondary PM requires the use of chemistry “modules” that simulate the reactions required for PM formation. A number of models with chemistry modules are under development, among those being the Canadian Meteorological Service’s Chemical Tracer Model (CTM; Environment Canada 1997a). Other efforts in Canada are based on incorporating aerosol modules and modifying acid deposition/oxidant models (Ontario Ministry of the Environment 1999). In the U.S., a number of models are used to simulate pollution episodes, especially for the California situation (references in Ontario Ministry of the Environment 1999, p.II.4-5). It is possible to estimate annual averages by running episodic models for a number of representative meteorological conditions and uses climatology to extrapolate to longer term averages. The Community Multiscale model within Models 3 (www.epa.gov) treats aerosol transport and formation, and the U.S. EPA is funding an upgrade of the Urban Airshed Model (UAM) to include an aerosol module. In Europe, the EMEP Program has utilized both Eulerian and Lagrangian models to investigate PM.

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5.4. Reduction Actions

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In May of 2000, based on scientific recommendations, Canada's Minister of Environment and Minister of Health announced their intention to declare PM10 toxic under the Canadian Environmental Protection Act (CEPA, Government of Canada 1999). Under CEPA, key industrial sectors in Canada are required to set emission reduction targets and timetables to meet those targets. In addition, a Canada-wide Standard for PM2.5 of 30 µg m-3 (24 hour averaging time), to be achieved by year 2010, was ratified by the Federal and Provincial governments. A wide range of actions to reduce emissions from vehicles, products and industry will have to be implemented to meet the Standard. Some of these, like vehicles and fuels, will be carried out by the federal government of Canada. Others, such as emission reductions from certain existing industrial sources, will be undertaken by provinces and territories. Emission reductions from a limited number of major industrial sectors that are of interest nationally will be achieved through joint efforts by the provinces/territories and the Government of Canada (www.ccme.ca). In 1997, the U.S. EPA added two new PM2.5 standards, set at 15 μg m-3 and 65 µg m, for the annual and 24-hour standards, respectively. The US EPA is beginning to collect data on PM2.5 concentrations, and beginning in 2002 based on 3 years of monitor data, EPA will designate areas that do not meet the new PM2.5 standards as non-attainment.

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6. Mercury

6.1. Introduction

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Mercury is a naturally occurring element that is present throughout the environment and in plants and animals. Human activities have increased the amount of mercury that is currently cycling in the atmosphere, in soils, and in lakes, streams and the oceans. Mercury concentrations in air are usually low and of little direct concern, but when mercury enters water, biological processes transform it to a very toxic and bioaccumulative form, known as methylmercury that builds up in fish and animals that eat fish. People are exposed to mercury primarily by eating fish (http://www.ec.gc.ca/air/mercury_e.shtml). Mercury vapor is chemically relatively inert and is therefore transported globally, becoming an international pollution issue and an ultra-long dispersal phenomenon. This explains it’s inclusion in the UN Protocol on heavy metals in the Convention on Long-Range Transboundary Air Pollution (CLRTAP). 6.2. Emissions and Transport Approximately 2000 tonnes of mercury are released globally to the air through man’s activities each year. Based on 1990 estimates, the USA released approximately 300 tonnes while Canada released some 30 tonnes. Through regulations and voluntary efforts by the major industrial sectors, Canada has reduced mercury emissions in excess of 50% since 1988 (www.ccme.ca).

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In Canada, airborne mercury is emitted mainly from base metal smelting plants and incinerators (Schroeder and Munthe 1998). In the USA, based on EPA’s National Toxics Inventory, the highest emitters of mercury to the air include coal-burning power plants, municipal waste combustors, medical waste incinerators and hazardous waste combustors (www.epa.gov/mercury/information.htm).

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In the atmosphere, mercury is transported by wind either as a vapor or as particles. Mercury reaches waters either through direct deposition or as run-off from soil after rain (Environmental Protection Agency 2000). Mercury deposition can occur very close to the source or, depending on the chemical form in which it is emitted, it can be transported great distances across international borders (Environmental Protection Agency 2000). The highest deposition rates in the USA occur in the southern Great Lakes, the Ohio Valley, the northeast and scattered areas in the southeast. Approximately 60 percent of the mercury deposition that occurs in the USA comes from domestic man-made sources of pollution. The remaining 40 percent comes from man-made sources located outside of the USA, re-emitted mercury from historic USA sources, and natural sources. Approximately two-thirds of USA emissions are transported outside their borders (www.epa.gov/mercury/information.htm). In Europe, heavy metal (including mercury) dispersion investigations have been promoted by the CLRTAP Protocol on heavy metals. The Meteorological Synthesising Centre – East section of EMEP coordinates investigations into heavy metals. The organization’s web-site (www.msceast.org) provides a description of natural and anthropogenic emissions with further references. 6.3. Investigation Methods (i) Monitoring

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In Canada, total ambient mercury is measured on a continuous basis at 11 sites across the country (www.msc.ec.gc/arqp/camnet_e.cfm). Precipitation mercury measurements are taken at a sub-set of these sites (Kellerhals et al. 2000). In the US, mercury wet deposition is measured at a sub-set (over 50 in year 2000) of the NADP sampling sites, and is called the Mercury Deposition Network (Sweet and Prestbo 1999). In Europe, the EMEP Chemical Coordinating Centre coordinates Mercury measurements in ambient air and precipitation. (ii) Modeling

Long range transport modeling has been undertaken in the USA to estimate the regional and national impacts of mercury emissions, based on the atmospheric chemistry of emitted elemental mercury (Petersen et al. 1995). The long range transport of mercury was modeled using the Regional Lagrangian Model of Air Pollution (RELMAP) atmospheric model (Environmental Protection Agency 1997) applied to cumulative mercury emissions from multiple mercury emission sources. The results of the RELMAP modeling were combined with a local scale atmospheric model (US EPA’s ISC3) to assess average annual atmospheric mercury concentrations

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in air and annual deposition rates from selected, individual sources (Environmental Protection Agency 1997). In Europe, efforts have also been recently made in modeling mercury transport and deposition under the EMEP program (Kallweit et al. 1998, 1999). 6.4. Reduction Actions

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Within Canada federal, provincial and territorial governments have agreed (Canadian Council of Ministers of the Environment, Quebec City, June 2000) to ratify a Canadawide Standard on mercury, paralleling similar actions in the USA Additional Canadawide Standards were also accepted in principle to reduce emissions of mercury in fluorescent lamps and dental amalgam wastes. Canada continues its implementation of mercury management options under the Canada/United States Great Lakes Binational Toxics Strategy in order to virtually eliminate mercury from human activities around the Great Lakes. In addition, Canada has signed and ratified the United Nations Protocol on heavy metals under CLRTAP, obliging Canada to control emissions of mercury, cadmium and lead from major stationary sources and some products. Finally, the signing of the Phase II North American Regional Action Plan on Mercury by Canada, the USA and Mexico under the North American Commission for Environmental Co-operation on June 12, 2000, will assist in investigating and remediating the effects of this pollutant.

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The USA government has announced that it will regulate mercury emissions from power plants. The regulations are expected by 2004. The US EPA has also issued regulations covering significant emitters that are said to reduce mercury emissions by 50% compared to 1990 levels (http://www.epa.gov/mercury/index.html). In addition, USA’s industrial demand for mercury dropped 75 percent from 1988 to 1997. The drop can be attributed to a number of actions including: federal bans on mercury additives in paint and pesticides; industry efforts to reduce mercury in batteries; increasing state regulation of mercury emissions and mercury in products; statemandated recycling programs; and, voluntary actions by industry. 7. Haze

7.1. Introduction

Haze is the phenomenon of reduced visibility; in this section we concentrate in haze issues on the Arctic, but issues of haze formation also occur in many major cities and regions worldwide as a result of either local or imported transboundary pollution emissions. The US National Parks Service has identified visibility impairment related to haze formation as a major issue and has devoted considerable resources to its measurement and control. Arctic haze has been found to consist largely of a collection of acidic sulfur compounds, black carbon, metals and some organics. The major problem associated with this haze is the associated health and ecosystem effects, rather than the loss of

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visibility per se (compared to the US National Parks haze issue). A sub-set of associated pollutants, the persistent organic pollutants (POPs), have a sufficiently different transport mechanism and source region to warrant separate discussion. However, this section will describe the general transport mechanisms for haze and most air pollutants into the Arctic. 7.2. Emissions and Transport

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Most contaminants are transported to the Arctic by air currents from parts of Asia, Europe and North America. Transport by air currents is the most important pollutant pathway into the Arctic (Arctic Monitoring and Assessment Program 1998). Longrange transport of soot and sulfates into the Arctic occurs predominantly during the winter and spring period. This is caused by an intense high-pressure system which develops over Siberia pushing the Arctic air mass far to the south, so that areas of Eurasia, with high pollutant emissions, are within the Arctic air mass. Once released into the Arctic air mass, they disperse towards the pole (Figure 6).

Figure 6. The mean circulation of the lower atmosphere during January and July as depicted by mean streamlines of the resultant winds (from Arctic Monitoring and Assessment Program 1998). The transport of contaminants during the Arctic winter is aided by low rates of precipitation scavenging in the relative absence of clouds over the areas dominated by high-pressure systems. In addition, low wind speeds and temperature inversions, caused by the cold winter weather, allow contaminants to accumulate in the atmosphere. Added to this, dry deposition rates tend to be low for air pollutant routes to the Arctic due to sparse vegetation and the general occurrence of surfaces of low pollutant absorbance. Finally, the relatively low amounts of sunlight, which would otherwise provide energy for the chemical transformation of these pollutants, provides

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conditions highly conducive to long-range pollutant transport. In contrast the haze issue in US National Parks is caused primarily from secondary PM formation (Wark et al 1998) and carbonaceous primary particles. Sources in North America and East Asia are not thought to provide major contributions to air pollution into the Arctic due the path of the air trajectories (Arctic Monitoring and Assessment Program 1998 and Figure 6). From these regions, air usually passes over large stretches of ocean where rain and snow cause marked precipitation scavenging. However, occasional “bursts” of pollution are thought to originate from these areas (Arctic Monitoring and Assessment Program 1998).

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The heavy metals that occur in Arctic haze, such as mercury, cadmium and lead, are present naturally in rocks and soil. Generally, human activities, such as mining, smelting and coal-burning power generation, release these metals to the environment (Arctic Monitoring and Assessment Program 1998). Smelter emissions from nonferrous metal production from sulfur-bearing ores cause the largest emissions of acidifying substances within the Arctic (Figure 7). Most smelter emissions come from the Nikel, Zapolyarnyy, and Monchegorsk complexes on the Kola Peninsula and from Norilsk in northwestern Siberia. In addition, these complexes tend to have lower levels of pollution control causing emissions to be extremely high (Arctic Monitoring and Assessment Program 1998). 7.3. Investigative Methods

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(i) Monitoring The Arctic Monitoring and Assessment Program (AMAP) is an international organization established to implement components of the Arctic Environmental Protection Strategy (AEPS) and is now a program group of the Arctic Council. The monitoring work within AMAP is based on existing national and international monitoring and research programs. Monitoring projects are carried out within each of the eight Arctic countries, and across borders under bilateral and multilateral agreements. In Canada, the Northern Contaminants Program co-ordinates air sampling at the three Canadian sites (Alert and Cape Dorset, both in the Territory of Nunavut, and Tagish in the Yukon Territory). In Russia, monitoring is, or has been, conducted at Dunai, in eastern Siberia, and Amderma, in the European Arctic region. Norway has also conducted monitoring near Spitzbergen. (ii) Modeling

Most pollutants making-up Arctic haze are described as one-hop compounds; that is, once deposited, or incorporated into the ecosystem they are not re-entrained into the atmosphere. For these compounds, three-dimensional numerical models have been applied and are described in Gregor et al. (1998)

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

Figure 7. An illustration of the interplay between a) contaminant emissions

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distribution for sulfur dioxide and b) frequency of atmospheric south-to-north transport, yielding c) a net annual input of sulfur to the Arctic as a function of longitude that favors Eurasian sources in the winter half of the year. This contaminant has a one-hop pathway in contrast to more volatile persistent organochlorines, PAHs, and mercury. (Arctic Monitoring and Assessment Program 1998) 7.4. Reduction Actions

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Signatory countries to the CLRTAP have committed to reductions in emissions and transboundary fluxes of many of the pollutants resulting in arctic haze under a number of Convention Protocols. The need for further protocols on heavy metals and POPs has been encouraged by Arctic countries and led to the conclusion of negotiations on these two sets of pollutants in February of 1998 (www.unep.org). Many of the Arctic countries have reduced emissions for various pollutants included in Arctic haze, sometimes driven by other issues (e.g., acid precipitation) at local or international levels, thus deriving “co-benefits” from respective reduction programs. In addition, organizations such as the Canadian International Development Agency have funded projects in the Russian Arctic to aid emissions reductions. 8. Persistent Organic Pollutants 8.1. Introduction

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Persistent organic pollutants (POPs) are highly toxic chemicals that are not easily broken down or converted in the environment. Outside of the Arctic, sources exist for a number of POPs; the main contaminants of concern include eight pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, and toxaphene), two industrial chemicals (PCBs and hexachlorobenzene, which is also a pesticide), and two unwanted by-products of combustion and industrial processes (dioxins and furans). Once deposited and incorporated into living tissues, these pollutants bioaccumulate, having long-term toxic effects (Arctic Monitoring and Assessment Program 1998). 8.2. Emissions and Transport

Generally, POPs are emitted from sources outside of the Arctic region and follow the same pathways into Arctic as for Arctic haze. However, their travels are interrupted by a number of step-wise occurrences of deposition, followed by re-entrainment into the atmosphere. Deposition can occur by condensation, adsorption or adherence into or on various substances. This multi-hop pathway, the so-called “Grasshopper” effect, together with their relative chemical inertness, causes these substances to be distributed globally. At some point in their journey, the winds are likely to carry them into the Arctic, where the cold climate and low evaporation rates trap POPs within the Arctic region. POP compounds have, until recently, been widely used as pesticides in poorer countries, but have been banned from use in richer countries. There are local sources of contaminants in the Arctic, such as mines and former military sites. However, these sources cannot account for all the types of

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contaminants or the wide geographic distribution of contaminants found there. Within the Canadian Arctic, PCBs from decommissioned DEW (Distant Early Warning) Line sites are thought to be sources, and dioxins/furans from smelters in Norway are examples of identified sources of POPs within the Arctic; other such sources probably exist but are presently unknown. 8.3. Investigation Methods (i) Monitoring

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Measurements of airborne POPs are carried out at the same measurement stations as for Arctic haze, and were described under that section. (ii) Modeling

Models for multi-hop compounds are much more complex than for single-hop compounds. In addition to the meteorology, multi-hop models also need to simulate how the contaminant moves between different environmental media, such as the atmosphere, the land, and the ocean. The dispersal domain is compartmentalized in order to simulate varying meteorological and climactic conditions encountered by the moving pollutant, with each compartment including atmospheric, land and water layers. Two models have been applied to orgnao-chlorines; the Bergen and Toronto models, which have also been combined (Gregor et al. 1998). 8.4. Reduction Actions

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In November 1996, the Executive Body for the CLRTAP moved negotiations forward on a protocol for POPs. The final draft text was signed on December 10, 2000 by Canada and 122 other countries. In its Federal budget for 2000, Canada committed $20 million over the next five years to projects that will help developing countries, and countries with economies in transition, to reduce or eliminate the release of POPs. The final text of the POPs Convention will go forward for formal approval, signature and ratification in Stockholm, Sweden, in May 2001. As part of that accord, most of the 12 POPs are subject to an immediate ban. However, a health-related exemption has been granted for DDT, which is still needed in many countries to control malarial mosquitoes (www.unep.org). Also in the case of PCBs, which have been widely used in electrical transformers and other equipment, governments may maintain existing equipment in a way that prevents leaks until 2025 to give them time to arrange for PCB-free replacements. In addition, a number of country-specific and time-limited exemptions have been agreed for other chemicals. Governments agree to reduce releases of furans and dioxins, which are accidental byproducts and thus more difficult to control, "with the goal of their continuing minimization and, where feasible, ultimate elimination." Glossary AEPS:

Arctic Environmental Protection Strategy

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NAMS: NADP: NAPS: Non-attainment area: PAHs: PAMS: ppm (Parts per million): PCBs: Photochemical oxidants: POPs: Primary pollutants:

in reference to pollutant emissions, the (positive) differences between a facility’s emissions and their allowable caps Arctic Monitoring and Assessment Program of human origin the preponderance of the atmosphere to enhance or suppress turbulence and vertical motions to accumulate in a biological system. However, it is commonly taken to measure the uptake over time of toxic substances that can stay in a biological system Canadian Air and Precipitation Monitoring Network (Canada) Clean Air Status and Trends Network (USA) (UN) Convention on Long-Range Transboundary Air Pollution Community Multiscale Air Quality modeling system for urban to regional scale air quality simulation of tropospheric ozone imaginary force required to divert the movement of air parcels over a flat surface to correctly simulate the effect of the rotation of the curved earth’s surface the formation of low pressure zones (cyclones) Dichlorodiphenyltrichloroethane is an organochlorine insecticide used to control mosquitoes and other insects Co-operative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe European Union a fixed frame of reference to track the movement of pollutants pollutant molecules or atoms with unpaired electrons, thus highly reactive a moving frame of reference to track the movement of pollutants National Air Monitoring Stations (USA) National Atmospheric Deposition Program (US) National Air Pollution Surveillance Network (Canada) State in the USA deemed not to have yet attained national air quality objectives polyaromatic hydrocarbons Photochemical Assessment Monitoring Stations (USA) concentration unit based upon dimensionless volume fraction of pollutant Polychlorinated Biphenyls atmospheric pollutants that involved in smog reactions (formation and so forth) persistent organic pollutants pollutants released directly from humanmade or natural sources

SLAMS: SPMS: (US) EPA:

State and Local Air Monitoring Stations (USA) Special Purpose Monitoring Stations (USA) (USA) Environmental Protection Agency

Allowances: AMAP: Anthropogenic: Atmospheric stability: Bioacummulative:

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CAPMoN: CASTNet: CLRTAP: CMAQ:

Coriolis (force):

Cyclogenesis: DDT: EMEP:

EU: Eulerian: Free radicals:

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Bibliography Arctic Monitoring and Assessment Program 1998. AMAP Assessment Report: Arctic Pollution Issues. Arctic Monitoring and Assessment Program (AMAP), Oslo, Norway. [Major international report describing arctic pollution issues.] Ayra, S.P. 1988. Introduction to Micrometeorology. Academic Press, San Diego, CA USA. [A good introductory text to micrometeorology.] Beveridge, P. 1999. IMPROVE Particulate Monitoring Network Procedures for Site Selection. Crocker Nuclear Laboratory, University of California (available from http://www.aqd.nps.gov/ard/vis/select22.pdf OR [email protected]). [A description of site selection procedures for the IMPROVE network.] Blackadaar, A.K. 1997. Turbulence and Diffusion in the Atmosphere. Springer-Verlag, Berlin, Heidelberg, New York. [A good introductory text to micrometeorology.]

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Brice, K.A., Penkett, S.A., Atkins, D.A.F., Sandalls, F.J., Bamber, D.J., Tuck, A.F. and Vaugham, G. 1984. Atmospheric measurements of peroxyacetyl nitrate (PAN) in rural south-east England: Seasonal variations winter photochemistry and long-range transport. Atmos. Environ. 18: 2691-2702. [A paper on PAN measurements.] Brook, J.R., Di-Giovanni, F., Cakmak, S., Meyers, T.P. 1997a. Estimation of dry deposition velocity using inferential models and site-specific meteorology: Uncertainty due to siting of meteorological towers. Atmos. Environ. 31(23): 3911-3919. [A paper on site-to-site variability of estimated dry deposition velocities.] Brook, J.R., Dann, T.F. and Burnett, R.T. 1997b. The relationship among TSP, PM10, PM2.5, and inorganic constituents of atmopsheric particulate matter at multiple Canadian locations. J. Air & Waste Manage. 47: 2-19. [A survey paper on airborne measurements of particulate matter in Canada.] Brook J., Zhang L., Di-Giovanni, F. and Padro J. 1999. Description and evaluation of a model of deposition velocities for routine estimates of air pollutant dry deposition over North America. Part I. Model development. Atmos. Environ. 33: 5037-5052. [A paper on a major regional deposition model developed for eastern North America.]

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Burnett, R.T., Dales, R., Krewski, D., Vincent, R., Dann, T. and Brook, J.R. 1995. Associations between ambient particulate sulphate and admissions to Ontario hospitals for cardiac and respiratory diseases. Am. J. Epidemiol. 142: 15-22. [A paper on links between health effects and ambient particulate matter levels.]

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Chang, J.S., Brost, R.A., Isaksen, I.S.A., Madronich, S. Middleton, P., Stockwell, W.R. and Walcek, C.J. 1987. A three-dimensional Eulerian acid deposition model: physical concepts and formulation. J. Geophys. Res. 92: 14681-14700. [A paper on the technical background behind a regional acid deposition model.]

Environment Canada 1997a. 1997 Canadian Acid Rain Assessment, V. II: Atmospheric Science Assessment Report. Environment Canada, Downsview, Ontario, Canada. [A major assessment report on the state of knowledge on acid rain in Canada.] Environment Canada, 1997b. Modelling of ground-level ozone in the Windsor–Québec City Corridor and in the Southern Atlantic Region. Report of the Windsor–Québec City Corridor and Southern Atlantic Region Modelling and Measurement Working Group. ISBN 1-896997-06-6. [A report on zone modeling application in southern Ontario, Canada.] Environment Canada 1998. Canada-United States Air Quality Agreement: 1998 Progress Report. Available from the International Joint Commission ([email protected] OR [email protected]). [Progress report on the International Agreement between Canada and the USA on transboundary air pollution.] Environmental Protection Agency, 1990. User’s Guide for the Urban Airshed Model, Volume I–VIII. EPA Publication Nos. EPA–450/4–90–007a–c, d(R), e-g, and EPA–454/B–93–004, respectively. U.S. Environmental Protection Agency, Research Triangle Park, NC (NTIS Nos. PB 91–131227, PB 91–

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131235, PB 91–131243, PB 93–122380, PB 91–131268, PB 92–145382, and PB 92–224849, respectively, for Vols. I–VII). [User’s guide for an air pollution model.] Environmental Protection Agency. 1997. Mercury Study Report to Congress, Volume III: Fate and Transport of Mercury in the Environment. United States Environmental Protection Agency, Office of Air Quality, Research Triangle Park, NC 27711, Report EPA-452/R-97-005. [A report to the US Congress on the transport of Mercury in the environment.] Environmental Protection Agency 2000. Deposition of Air Pollutants to the Great Waters: Third Report to Congress. United States Environmental Protection Agency, Office of Air Quality, Research Triangle Park, NC 27711, Report EPA-453/R-00-005. [A report to the US Congress on the deposition of air pollutants to the Great Lakes.]

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Faiz, A., Sinha, K., Walsh, M. and Varma, A. 1990. Automotive Air Pollution: Issues and Options for Developing Countries. The World Bank, August 1990, WPS 492. [A report by the World Bank on air pollution issues caused by automobiles.] Finlayson-Pitts, B.J. and Pitts, J.N. Jr. 1986. Atmospheric Chemistry: Fundamentals and Experimental Techniques. Wiley-Interscience, Toronto. [A good introductory text on atmospheric chemistry.] Government of Canada 1999. Canadian Environmental Protection Act. http://www.ec.gc.ca/cepa. [A copy of the Canadian Environmental Protection Act.]

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Gregor, D.J., Loeng, H. and Barrie, L. 1998. The Influence of Physical and Chemical Processes on Contaminant Transport into and within the Arctic. In: Arctic Monitoring and Assessment Program 1998. Chapter 3, pp. 25-116, AMAP Assessment Report: Arctic Pollution Issues. Arctic Monitoring and Assessment Program (AMAP), Oslo, Norway. [Part of the AMAP report describing the physical and chemical processes affecting transport within the arctic.] Hov, O. 1984. Modelling of the long-range transport of peroxyacetyl nitrate to Scandinavia. J. Atmos. Chem. 1: 187-202. [A paper on modeling long-distance PAN movement in Scandinavia.] Hov, O. Becker, K.H., Builtjes, P. Cox, R.A. and Kley, D. 1986. Evaluation of Photooxidants-Precursor Relationship in Europe. CEC, Brussels, AP/60/87. Air Pollut. Res. Rep. 1. [A report on photo-oxidant precursors in Europe.]

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Irving, P.M. 1991. Acidic Deposition: State of the Science and Technology. Volume I: Emissions, Atmospheric Processes, and Deposition. The US National Acid Precipitation Assessment Program, NAPAP Office of the Director, Washington DC, USA. [A major US assessment report on the state of the science on acid rain as it stood in the early 1990’s.]

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Kallweit D., Loblich K. and Ihie, P. 1998. Niederschlagsanalysen 1997. Depositionsmessnetz des Umweltbundesamtes. Das jahrliche Bericht von Institut fur Energetik und Umwelt. Leipzig, Germany. [A report on mercury deposition modeling under the EMEP program.] Kallweit D., Loblich K. and Ihie, P. 1999. Niederschlagsanalysen 1998. Depositionsmessnetz des Umweltbundesamtes. Das jahrliche Bericht von Institut fur Energetik und Umwelt. Leipzig, Germany. [A report on mercury deposition modeling under the EMEP program.] Kellerhals, M., S. Beauchamp, W. Belzer, P. Blanchard, F. Froude, B. Harvey, K. McDonald, M. Pilote, L. Poissant, K. Puckett, W.H. Schroeder, A. Steffen, R. Tordon. 2000. Temporal and spatial variability of total gaseous mercury in Canada: Preliminary results from the Canadian Atmospheric Mercury Measurement Network (CAMNet). In proceedings of The International Conference on Heavy Metals in the Environment, August 6-10, 2000, Ann Arbor, Michigan, USA. [A preliminary Canadian report on mercury variation.] Lubkert, B., Lieben, P., Grosch, W., Jots, D. and Weber, E. 1984. Oxidant Monitoring Networks – Oxidant Monitoring Data. Report from an International Workshop, 23-25 October 1984. Schauinsland, Federal Republic of Germany/OECD Environment Directorate, Ministry of the Interior of the Federal Republic of Germany, Unweltbundesamt, Berlin. [A report on zone in Europe including a description of damage to vegetation.] Lutgens, F.K. and Tarbuck, E.J. 1986. The Atmosphere: An Introduction to Meteorology. 3rd. Edn. Prentice-Hall, Inc. Englewood Cliffs, New Jersey, USA. [A good introductory text to meteorology.]

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

Meyers T.P., Finklestein P., Clarke J., Ellestad T. and Sims P.F., (1998) A multi-layer model for inferring dry deposition using standard meteorological measurements. J. Geophys. Res., 103: 2264522661. [A description of the theoretical background to the dry deposition model used for the US National Atmospheric Deposition routine monitoring program.] Oke, T.R. 1978. Boundary Layer Climates. Methuen, London and New York. [A good introductory text to micro-cliamtology.] Ontario Ministry of the Environment 1998. Ontario’s Smog Plan: A Partnership for Collective Action. Ontario’s Smog Plan – Secretariat, Ontario Ministry of the Environment, Toronto, Ontario. [A description of Ontario (Canada) provincial government actions to deal with Smog.] Ontario Ministry of the Environment. 1999. A Compendium of Current Knowledge on Fine Particulate Matter in Ontario. Ontario Ministry of the Environment, Toronto, Canada. [A recent review on airborne fine particulate matter with emphasis on the province of Ontario, Canada.]

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Overrein, L.N. 1972, Sulfur pollution patterns observed: Leaching of calcium in forest determined. Ambio 1: 143-145. [A paper on early European work on acid rain.] Overrein, L.N., Seip, H.M. and Tollan, A. 1980. Acid Precipiation – Effects on Forest and Fish. Final Report of the SNSF Project, 1972-1980. RECLAMO, Oslo, Norway. [A report on early European work on acid rain.] Petersen, G., Iverfeldt, Å. and Munthe, J. 1995. Atmospheric mercury species over Central and Northern Europe: Model calculations and comparison with observations from the Nordic Air and Precipitation Network for 1987 and 1988. Atmos. Environ. 29: 47-68. [A paper on modeling airborne mercury dispersion and deposition.] Reist, P.C. 1984. Introduction to Aerosol Science. Macmillan Publishing Company, New York. [A good introductory text to aerosol science.] Schroeder, W.H. and J. Munthe. 1998. Atmospheric mercury: An overview. Atmos. Environ. 32: 809822. [An overview paper on atmospheric mercury with emphasis on north America, especially Canada.] Seinfeld, J.H. 1986. Atmospheric Chemistry and Physics of Air Pollution. John Wiley & Sons, New York, Toronto. [A god introductory text to atmospheric chemistry.]

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Stieb, D.M., Beveridge, R.C., Brook, J.R., Smith-Doiron, M., Burnett, R.T., Dales, R.E., Beaulieu, S., Judek, S. and Mamedov, A. (2000). Air pollution, aeroallergens and cardiorespiratory emergency department visits in Saint John, Canada. J. Exposure Analysis and Env. Epidemiology 10: 461-477. [A paper on the relationship between air pollution, including bioaerosols, and health impacts.]

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Stull, R.B. 1997. An Introduction to Boundary Layer Meteorology. Kluwer Academic Publishers. Dordrecht, Boston, London. [A good introductory text on boundary-layer meteorology.] Sweet, C.W. and Prestbo, E. 1999. Wet Deposition of Mercury in the U.S. and Canada. Presented at "Mercury in the Environment Speciality Conference", September 15-17, 1999, Minneapolis, MN. Proceedings published by Air and Waste Management Association, Pittsburgh, PA. [A paper on the deposition of mercury, in precipitation, in north America.] Tsyro, S.G. 1998a. 12-year acidification trends over Europe with the Lagrangian model: quality assessment. EMEP/MSC-W Status Report 1/98, Part 1: Estimated dispersion of acidifying and eutrophying compounds and comparison with observations, EMEP/MSC-W Status Report 1/98, pp. 79102. Norwegian Meteorological Institute, Oslo, Norway. [A report on EMEP efforts to model dispersion of acidifying compounds.] Tsyro, S.G. 1998b. Description of the Lagrangian Acid Deposition Model. EMEP/MSC-W Status Report 1/98, Part2: Numerical Addendum. EMEP/MSC-W Status Report 1/98, Appendix A. Norwegian Meteorological Institute, Oslo, Norway. [A report describing the EMEP Lagrangian acid deposition model.] United Nations, 1991. Assessment of Long-range Transboundary Air Pollution. Air Pollution Studies 7 prepared by the Economic Commission for Europe (Geneva). UN Publication ECE/EB.AIR/26. [A UN report on general aspects of transboundary air pollution.]

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ENVIRONMENTAL MONITORING – Transboundary Air Pollution - Franco DiGiovanni and Philip Fellin

Vedal, S. 1997. Ambient Particles and Health: Line that Divide. J. Air & Waste Manage, Assoc. 47: 551-581. [A critical review of the relationship between airborne particulate matter and human health relationships.] Venkatram, A., Karachandani, P.K. and Misra, P.K. 1988. Testing a comprehensive acid deposition model. Atmos. Environ. 22: 737-747. [Early work on testing a regional Canadian model of acid deposition.] Wark, K., Warner, C.F. and Davis, W.T. 1998. Air Pollution: Its Origin and Control. 3rd Edn. Addison Wesley, Dons Mills, Ontario. [A good introductory text to air pollution in general, with emphasis on US examples.]

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WHO-EMEP 1999. Health risk of particulate matter from long range transboundary air pollution: Preliminary Assessment. WHO, Bilthoven, The Netherlands. [A WHO report on health risks from particulate matter from long range transportation.] Biographical Sketches

Philip Fellin With 29 years in the environmental field, Mr. Fellin has specific expertise in: -- measuring air pollutants -- indoor air quality and occupational hygiene measurements -- developing analytical methods, instrumentation and methods for sampling airborne compounds -- designing studies to investigate chemical and physical processes in the atmosphere such as the long range transport of airborne pollutants (acid rain), urban air pollution (smog), fugitive emissions from industrial facilities, and -- measuring personal exposures in occupational, indoor and transportation environments In addition, he has been involved in the measurement of airborne toxic compounds in both populated and remote areas such as the Arctic, executed environmental impact assessments for new industrial facilities and delivered training programs on air pollution measurement and assessment in Canada and internationally.

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Franco DiGiovanni has had 10 years dispersal modeling experience and is presently Air Quality and Dispersal Modeler for Airzone One Ltd. He has particular expertise in particulate matter dispersal modeling and measurement. He is also experienced in field program execution aimed at model verification. In addition, he has responsibilities in the bioaerosol (ambient and indoor) and indoor air quality sectors, and in emissions estimation and regulatory compliance.

To cite this chapter Franco DiGiovanni and Philip Fellin, (2006) ,TRANSBOUNDARY AIR POLLUTION, in Environmental Monitoring , [Eds.Hilary I. Inyang, John L. Daniels], in Encyclopedia of Life Support Systems (EOLSS), Developed under the Auspices of the UNESCO, Eolss Publishers, Oxford ,UK, [http://www.eolss.net]

©Encyclopedia of Life Support Systems (EOLSS)