Deterioration of copper and bronze caused by acidifying air pollutants

The ‘ICP on effects on materials’ was launched in 1985, within the framework of the Convention on Long-range Transboundary Air Pollution with the aim to find an approach for clearing the main gaps in the knowledge about material degradation caused by environmental impacts. The project was organized as a staggered8 year's material exposure programme accompanied by an extensive measuring programme for environmental parameters. During the evaluation of the 4 years data set it took shape that the most efficient parameters for quantifying the material degradation are the mass loss and especially for copper the corrosion volumes. Bronze already reacts extremely sensitive on low SO₂ concentrations. The starting corrosion rate for copper is suprisingly high. A strong impact of chloride on the formation of pin holes for sheltered copper could be detected without showing high mass loss. At simultanous presence of ozone the corrosive action is catalysed by it's oxidation power and leads to severe mass loss. Based upon the 4 years data set for most of the materials preliminary dose-response-functions have been prepared. For the first time a synergetic effect of SO₂ and ozone has been demonstrated in a field exposure.     

Soil Contamination Caused by Emergency Bio-Reduction of Catastrophic Livestock Mortalities

Water, Air, & Soil Pollution - The variations of tropospheric ozone levels was assessed for the first time in the Boukornine National Park (N.E. Tunisia) by detection of leaf injury development...     

Mapping critical levels of ozone,sulfur dioxide and nitrogen dioxide for crops,forests and natural vegetation in the United States

Air pollution abatement strategies for controlling nitrogen dioxide, sulfur dioxide, and ozone emissions in the United States focus on a ‘standards-based’ approach. This approach places limits on air pollution by maintaining a baseline value for air quality, no matter what the ecosystem can or cannot withstand. In this paper, we present example critical levels maps for the conterminous U.S. developed using the ‘effects-based’ mapping approach as defined by the United Nations Economic Commission for Europe's Convention on Long-Range Transboundary Air Pollution, Task Force on Mapping. This approach emphasizes the pollution level or load capacity an ecosystem can accommodate before degradation occurs, and allows for analysis of cumulative effects. We present the first stage of an analysis that reports the distribution of exceedances of critial levels for NO₂, SO₂, and O₃ in sensitive forest, crop, and natural vegetation ecosystems in the contiguous United States. We conclude that extrapolation to surrounding geographic areas requires the analysis of diverse and compounding factors that preclude simple extrapolation methods. Pollutant data depicted in this analysis is limited to locationally specific data, and would be enhanced by utilizing spatial statistics, along with converging associated anthropogenic and climatological factors. Values used for critical levels were derived from current scientific knowledge. While not intended to be a definitive value, adjustments will occur as the scientific community gains new insight to pollutant/receptor relationships. We recommend future analysis to include a refinement of sensitive receptor data coverages and to report relative proportions of exceedances at varying grid scales.     

Mapping Ozone Critical Levels for Vegetation in Central Italy

Within the framework of the UN-ECE Convention on Long-Range Trans-boundary Air Pollution, critical ozone levels for forest trees and crops have been determined. This paper shows the mapping results of short and long-term threshold exceedances in an area of Central Italy. Eighty-thousand hourly mean ozone concentrations were recorded and computed to evaluate the potential distribution of the pollutant in the area. The results suggest that the threshold is frequently exceeded in the summer, and this may be very critical for the plants' health.     

Developing optimal abatement strategies for the effects of sulphur and nitrogen deposition at European scale

Integrated Assessment Models were successfully used to provide input to the negotiations for the Oslo Protocol on Further Reductions of Sulphur Emissions, finalized within the United Nations Economic Commission for Europe Convention on Long-range Transboundary Air Pollution in Oslo in June 1994. The techniques developed within this framework will be extended now to the simultaneous analysis of sulphur and nitrogen deposition. In addition to acidification, atmospheric deposition of nitrogen contributes to eutrophication of certain ecosystems, through a nutrient effect, and originates from the long-range transport of emissions of both oxidised and reduced nitrogen (NO_x and NH₃). Modelling reductions in nitrogen deposition thus introduces a need to establish multi-pollutant multi-effect modelling techniques. This paper investigates the development of a model set up to examine reductions of these pollutants in an economically and environmentally efficient manner. The control of nitrogen deposition encompasses action across several economic sectors, particularly the power, transport and agricultural sectors. Combining sulphur and nitrogen deposition limits on a European scale will require a flexible modelling approach and the issues governing possible approaches are presented.     

Measurements of Ozone Deposition to Vegetation Quantifying the Flux,the Stomatal and Non-Stomatal Components

Water, Air, &; Soil Pollution - Ozone deposition to vegetation represents the major sink for boundary layer ozone and yet the underlying mechanism of reaction and uptake at the surface is poorly...     

Establishing critical levels for the effects of air pollution on vegetation

In recent years, international air pollution effects research has focused on setting critical levels of pollutants, above which adverse effects occur on sensitive receptors. Once established, these levels are used to determine the geographical extent of exceedance for different vegetation categories and ultimately in the development of international protocols for pollution control within the Convention on Long-range Transboundary Air Pollution. Ideally, the critical level for each pollutant and vegetation category should have a relatively simple definition to allow ease of mapping. Nevertheless, the definitions need to be sufficiently robust to apply to sensitive vegetation growing in a diverse range of climates. The restrictions imposed by these criteria have led to complex and delicate negotiations between scientists from the UN/ECE* region. Data for the direct effects of air pollutants on vegetation have been carefully reviewed for applicability to critical levels. To date, critical levels have been set for the effects of SO₂, ozone, NOx and NH₃ on crops, trees and natural vegetation. The use of effects data to establish these levels is critically assessed in this paper in relation to current and future requirements for mapping.     

Numerical Simulation of the Springtime Trans-Boundary Air Pollution in East Asia

Water, Air, &; Soil Pollution - During the spring, the high concentrations of ozone (O3) and aerosols are frequently observed aloft in Japan. Such episodes supposedly are caused by the...     

An Integrated Feasibility Study on Designing Remediation Systems for Petroleum-Contaminated Sites

Water, Air, & Soil Pollution - This paper presents an integrated feasibility study on designing systems for remediating petroleum-contaminated sites. Its consists of components of...     

An integrated analysis of sulfur emissions,acid deposition and climate change

This paper presents one of the first integrated analyses of acidification and climate change on a geographically-detailed basis, and the first linkage of integrated models for acid deposition (RAINS) and for climate change (IMAGE 2). Emphasis in this paper is on Europe. Trends in driving forces of emissions are used to compute anthropogenic SO₂ emissions in 13 world regions. These emissions are translated into regional patterns of sulfur deposition in Europe and global patterns of sulfate aerosols using source-receptor matrices. Changes in climate are then computed based on changes in sulfate and greenhouse gases. Finally, we compute ecosystem areas affected by acid deposition and climate change based on exceedances of critical loads and changes in potential vegetation. Using this framework, information from global and regional integrated models can be used to link sulfur emissions with both their global and regional consequences. Preliminary calculations indicate that the size of European area affected by climate change in 2100 (58%) will be about the same as that affected by acid deposition in 1990. By the mid 21st century, about 14% of Europe's area may be affected by both acid deposition and climate change. Also, reducing sulfur emissions in Europe will have both the desirable impact of reducing the area affected by acid deposition, and the undesirable impact of enhancing climate warming in Europe and thus increasing the area affected by climate change. However, for the scenarios in this paper, the desirable impact of reducing sulfur emissions greatly outweighs its undesirable impact.     

The Chemical Transformations of Chromium in Natural Waters – A Model Study

Water, Air, &; Soil Pollution - A hybrid chemical kinetic and equilibrium model has been developed to quantitatively assess the dynamic oxidation-reduction (redox) transformations of chromium in...     

Integrated assessment models as a basis for air pollution negotiations

During the last decade the issue of integrated assessment has received attention both in the scientific literature and in the negotiation of international air pollution agreements. More than often this literature does not differentiate between the integrated assessment as a process and the development and use of models as a tool for calculating the potentials of various scenarios. This paper describes the difference between the process and the tool, and illustrates this using the negotiations leading to the Second Sulfur Protocol (June 1994, Oslo). The situation in Europe (with a highly visible interaction between science and policy) will be compared with the United States (where new legislation was passed before the integrated assessment was finished). Further, the role of integrated assessment models in these negotiations will be discussed with special attention for the interaction between model builders and model users. Lessons from the recent European experience will be drawn. These include lessons for future protocols on acidification, and combined ozone/acidification/eutrophicationprotocols. These lessons will deal with the scale of the problem, the scope of the integrated assessment models, the development of models in parallel with scientific development and the various modes of interaction with the policy community.     

Modelling ozone deposition fluxes: The relative roles of deposition and detoxification processes

A new Model of Ozone Deposition and Detoxification (MODD) is presented. This model describes stomatal ozone uptake and deposition on external plant surfaces and soil; it accounts for diurnal variability of detoxification processes and reactive ozone uptake on cuticular waxes and soil surface. The mechanistic modelling of plant defense reactions is based on the Plöchl et al. (2000) detoxification model in which the dynamics of apoplast chemistry are considered. To estimate ozone deposition fluxes on cuticular waxes and soil surface, we use a revised version of the Morrison and Nazaroff (2002) model developed to account for ozone uptake on material surfaces. This model which has been fully integrated with a soil-plant-atmosphere continuum model ensures a complete coupling between stomatal conductance and O₃ exchanges between leaves and the atmosphere. The observed diurnal variations in stomatal conductance which largely control the influx of O₃ into the leaf are well reproduced. Model simulations point out that the pool of ascorbate located in the mesophyll cell wall plays a significant role in the detoxification of O₃. Besides stomatal conductance, it is the key process involved in the control of ozone flux to the cell wall. A decrease in the pool of ascorbate lengthens the chemical lifetime of O₃ in the cell wall then the virtual apoplastic resistance is found to increase with decreasing ascorbate. Although the atmospheric ozone concentration increases as the weather becomes hot and dry, the virtual apoplastic resistance follows the same trend, indicating a decrease of the ascorbate pool in the mesophyll cell wall. Results also indicate that for the pre-senescence period 57% of the ozone is deposited onto the cuticular surfaces, 4% on soil and only 37% is absorbed by stomata. The comparison of modelled and measured data reported in this study indicates that the model is capable of predicting the major features of the patterns of total ozone flux.     

Clover Sweden — A national three-year study of the effects of tropospheric ozone on Trifolium subterraneum,L.

In 1992 a cooperative project, Clover Sweden, was initiated. The aim was to study if subterranean clover could be used as a bioindicator in the different climate zones in Sweden by studying the impact of ambient ozone concentrations on this species in different parts of the country during three consecutive summer seasons. Plants of subterranean clover, Trifolium subterraneum, L., were exposed to ambient air at 24 sites from north to south Sweden. The project was designed to be compatible with the international programme, ICP Crops within the UNECE and the Convention on Long Range Transboundary Air Pollution. The results showed that subterranean clover is a useful bioindicator of ozone in all agricultural areas of Sweden, with the exception for very cool and rainy summers resulting in poor growth of the plants. In 1992, and especially in 1994, ozone injury was detected at almost all sites in Sweden, reflecting the higher ozone levels of those summers as compared to 1993, when ozone concentrations were generally low and not much injury was detected. Typical injury was chlorotic and bifacial necrotic lesions on parts of the leaf surface. It is concluded that at mean ozone concentrations of 25 ppb (24 h mean) and 30 ppb (7 h mean) there is a potential risk for injury on 10% of the leaves. When % injured leaves was plotted against AOT (Accumulated exposure Over a Threshold) using different thresholds, it became obvious that a threshold of 20 ppb ozone should be used in order to fully protect from leaf injury under Swedish conditions.     

Evaluation of Tobacco Cultivars as Bioindicators and Biomonitors of Ozone Phytotoxical Levels in Catalonia

A field study was conducted from May to October 1995 to assess ozone (O₃) phytotoxicity in Catalonia (NE Spain) by determining a percentage value of leaf area injured by ozone on three tobacco cultivars, Bel-W3, Bel-C and Bel-B as bioindicators. Colorimetric parameters were also determined in an effort to have an objective assessment of ozone injury. The study was conducted simultaneously on eight sites where ozone levels and several meteorological parameters were continuosly monitored. Two sets of plants were used at each site. The first one was composed of six plants of each cultivar which were changed every two weeks while the second one involved two plants of each cultivar which were kept in the plots throughout the whole experimental period. Open Top Chambers were also used to test the response of the three cultivars to ozone under controlled conditions. The ozone levels correlated well with ozone injury on the Bel-W3 cultivar but not as well on the other two cultivars. The ozone levels did not fully account for all the observed injury. The response of tobacco plants to ozone concentrations and therefore its biomonitoring capacity depended also on different environmental conditions linked to stomatal behaviour such as temperature, humidity, wind or altitude. These environmental conditions had some effects on the intensity of Ozone injury. Ozone concentrations accumulated over a threshold of 60 ppb (AOT60) when VPD was below 1 KPa. Correlated well with the ozone injury and best explained the intensity tobacco injury symptoms. For large plants growing throughout the whole period of study, Bel-C was the best indicator cultivar for AOT60 over the 3 days prior to the last ozone injury assessment. The colorimetric parameters were indicators of seasonal changes but they were not good ozone damage indicators. It is concluded that tobacco cultivars were good bioindicators but meteorological and other environmental factors need to be considered in there use as biomonitors.     

Effect of Water Table Level on Metal Mobility at Different Depths in Wetland Soils of the Scheldt Estuary (Belgium)

Water, Air, & Soil Pollution - Many management strategies to improve the health of Chesapeake Bay focus on reducing losses of sediments and nutrients from agricultural land. Plot-scale studies...     

Evaluation of Premature Mortality Caused by Exposure to PM2.5 and Ozone in East Asia: 2000, 2005, 2020

The aim of this study is to assess the premature mortality risks caused by exposure to particulate matter with aerodynamic diameter less than 2.5???m (PM_2.5) and ozone elevated concentrations for the years?2000, 2005, and 2020 in East Asia. The spatial distributions and temporal variations of PM_2.5 and ozone concentrations are simulated using the Models-3 Community Multiscale Air Quality Modeling System coupled with the Regional Emission Inventory in Asia. The premature mortality risks caused by exposure to PM_2.5 and ozone are calculated based on a relative risk (RR) value of 1.04 (95?% confidence interval (CI): 1.01?C1.08) for PM_2.5 concentrations above the annual mean limit of 10???g?m^?3 taken from the World Health Organization?CAir Quality Guideline and based on a RR value of 1.003 (95?% CI: 1.001?C1.004) for ozone concentration above 35?ppb of the SOMO35 index (the sum of ozone daily maximum 8-h mean concentrations above 35?ppb). We demonstrate one of the implications of the policy making in the area of environmental atmospheric management in East Asia by highlighting the annual premature mortalities associated with exposure to PM_2.5 concentrations that just meet an annual mean concentration of 10???g?m^?3, as well as ozone concentrations that have a daily zero SOMO35 index in vulnerable places. Our results point to a growing health risk that may endanger human life in East Asia. We find that the effect of PM_2.5 on human health is greater than the effect of ozone for the age group of 30?years and above. We estimate the corresponding premature mortality due to the effects of both ozone and PM_2.5 in East Asia for the years?2000 and 2005 to be around 316,000 and 520,000 cases, respectively. For future scenarios of the year?2020, policy succeed case, reference, and policy failed case, the estimated annual premature mortality rates are 451,000, 649,000, and 1,035,000 respectively.     

Descriptive apportionment of lead in housedust by automated sem

Water, Air, & Soil Pollution - Quantifying sources of aerosol derived materials is an important task in environmental pollution research. Receptor modeling using automated scanning electron...     

Estimation of source-receptor matrices for deposition of NOx-N

The contributions of the anthropogenic sources of NO_x from various combinations of contiguous U.S. states or Canadian provinces to integrated deposition across selected states or provinces are estimated with the Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model. The model assumes linearity between emissions and deposition, and uses the same parameterization methods, although with different rates, as in simulations of transport and deposition of SO_X. Vertical distributions of emissions for the two classes of pollutants are substantially different in the gridded inventories used in simulations, with a weighted mean effective emission height of 160 m for NO_X and 310 m for SO_X. This might be expected to lead to an effective transport distance before deposition shorter for NO_X than for SO_X. However, the calculated fraction of NO_X emissions deposited within the contiguous United States and Canada south of 60 deg N (57%) is not greatly different from the fraction calculated for SOX emissions (54%). This suggests that there may be compensating factors in the horizontal distribution of NO_X emissions, and in the lower dry deposition velocities for NO/NO₂ than for SO₂ in ASTRAP.