Acidic pollutants, sources

As treated in other chapters of this book, air masses often transport acidic pollutants thousands of kilometres from their original source prior to deposition. Because air mass and storm movements tend to follow regular patterns, there is a strong linkage between the sources of pollutants and the areas that receive the acidic deposition. In eastern North America, the air mass movements and storm tracks are, on the average, from southwest towards the northeast. This serves to carry the emitted pollutants from the industrial "heartland over the more rural and comparatively pristine area of the northeast United States and southeastern Qmada (14). The spatial distribution of sulphate deposition over the eastern United States and Canada in 1980 is shown in Figure 4 (17). 

Acidolysis is a similar weathering reaction to hydrolysis in that is used to weather minerals, but in this case the source of is not water but organic or inorganic acids. Humic and fulvic acids (discussed in Section 8.3.2), carbonic acid, nitric or sulfuric acid, and low-molecular-weight organic acids such as oxalic acid can all provide H to weather minerals. All of these acids occur naturally in soils in addition nitric and sulfuric acid can be added to soil by acid pollution. The organic acids are prevalent in the... 

Kenneth Warren. Chemical Foundations The Alkali Industry in Britain to 1926. Oxford Clarendon Press, 1980. Source for family shops changing to giant factories Liebig quotation plant sources of alkalis Leblanc s experiment Victorians like Leblanc factories reduction in hydrochloric acid pollution cost of pollution abatement electrolysis and 3 raw material units make 1 unit of product. 

Acid rain arises from the oxidation of S02 and N02 in the troposphere to form sulfuric and nitric acids, as well as other species, which are subsequently deposited at the earth s surface, either in precipitation (wet deposition) or in dry form (dry deposition). The contribution of organic acids has also been recognized recently (see Chapter 8). These oxidation and deposition processes can occur over relatively short distances from the primary pollutant sources or at distances of a fOOO km or more. Thus both short-range and long-range transport must be considered. 

Although both types of pollution sources present a serious problem, point sources can be controlled, at least in principle. Nonpoint sources, however, are difficult to control. Sources and types of nonpoint pollution in impacted rivers and lakes in the United States include agriculture, land disposal, construction, hydromodification, urban runoff, and silviculture, resource extraction. The pollutants in these sources include sediment, nutrients, toxins, pesticides, salinity, and acidity (Institute, 1988). Looking at these lists, one can easily deduce that solvents play roles in the pollution of water. 

Acid precipitation resulting from sulfuric acid (and nitric acid) has the ability to significantly lower the pH. The reactions forming sulfuric acid in the atmosphere often take several days therefore acid precipitation can fall several hundred kilometers away from the pollution source. This has led to transnational negotiations and agreements in an attempt to control sulfur emissions, the precursor to acid precipitation. 

If released into the atmosphere, this SO2 reacts with water to form acid rain. A great deal of study is directed toward removing and utilizing the S02 from stack gases and the conversion of the SO2 into sulfuric acid. This source of sulfuric acid has decreased the amount of acid produced by the burning of elemental sulfur and has helped in the prevention of air pollution. 

There has been considerable effort to solve and diminish ecological and environmental problems such as air pollution, acid rain, soil pollution, and etc [1]. It has been well known that the acidic gases, such as, SO2 and NO, are major components of air pollution. Carbons have been used as not only a reducing agent itself but also catalyst support for the purpose of removing pollution sources such as NO, SO, and etc [2-4]. 

Intensive investigations of the sulfur dynamics of forest ecosystems in the last decade can be attributed to the dominant role of sulfur as a component of acidic deposition. Studies in forested catchments include Fuller et al. (1986), Mitchell et al. (1989), Stam et al. (1992), and Andersson et al. (1992). Sulfur with a distinctive isotopic composition has been used to identify pollution sources (Krouse et al., 1984), and has been added as a tracer (Legge and Krouse, 1992 Mayer et al., 1992, 1993). Differences in the natural abundances can also be used in systems where there is sufhcient variation in the 5 " S of ecosystem components. Rocky Mountain lakes (USA), thought to be dominated by atmospheric sources of sulfate, have different 5 " S values than lakes believed to be dominated by watershed sources of sulfate (Turk et al., 1993). 

NO in combination with SOp has a synergistic corrosion effect especially indoors on electrical contact materials, copper and steel. The influence of acid precipitation may differ for different metals and depends also on the pollution level. The atmospheric corrosion of metals due to acid deposition is in most regions mainly a local problem restricted to areas close to the pollution source. 

The atmospheric corrosion of metals caused by acid deposition is mainly a local problem restricted to areas close to the pollution source. 

Air pollution sources in the United States and Canada currently emit more than 25 million tons of sulfur dioxide each year. SO2 and wet acidic deposition are believed to cause damage to aquatic life, crops, forests, and materials. The effects on materials include damages to common construction materials including galvanized steel (zinc), paint, copper, building stones and mortar, as well as damages to cultural or historic objects and buildings. 

Another simple test that distinguishes acids from bases is the reaction of acids with ionic compounds that contain the carbonate ion,, to form carbon dioxide gas, water, and another compound, as shown in Figure 14.3. A similar reaction, also shown in Figure 14.3, is the source of the destructive action of acidic pollution on marble and limestone sculptures. Bases do not react with carbonates. 

The minimisation of gas emissions as CO2, SO2, NO, and other acid gases is a key topic in sustainable process design. This problem can be handled only by a systematic approach of all the pollution sources generated by energy integration, namely the utility system, heat recovery and cogeneration, as well as by process modifications. 

Non-point sources are pollution sources that are rather diffuse in nature. Good examples of this type of pollution are water contamination caused by agricultural runoff or acid rain. Controlling and regulating this type of pollution is much more difficult because you can t identify a particular company or individual as the polluter. In recent years, federal and state agencies have attempted to address non-point source pollution. The Clean Water Action Plan of 1998 was one such attempt that focused on watersheds and runoffs. 

Nevertheless Section 9 of the report does examine the impact on buildings of acid pollutants/ since in many urban environments this damage can be quite widespread. Also the report does consider the importance of distance from sources as a factor in influencing the likely type of pollutant which may cause damage/ its deposition level and resultant impact. On the other hand respiratory health effects caused by high urban SO2 with particulate concentrations was considered not to be part of the acid rain phenomenon. 

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