Coal, combustion emissions, source sulfate

A major objective of these CMBs was to determine primary and secondary contributions from coal-fired plants. Arsenic and Se are often used as "markers" for primary emissions from coal-fired plants (10), but Table II shows that substantial amounts of these elements are associated with regional sulfate, most of which results from transport from distant coal-fired plants. The regional sulfate component was based largely on FA of fine particles collected in Shenandoah Valley (4), which mainly represents material transported into the area from the west. As previously discussed (11), broadly similar components can be constructed from data of Thurston and Spengler (6), Pierson et al. (12), and Rahn and Lowenthal (13). At present, we don t know if this component is appropriate for samples collected within the ORV. Also, industrial sources such as copper plants and iron and steel mills interfere with some elements that might otherwise be good markers for coal combustion. Gallium shows... 

Particle precursor gases are emitted into the atmosphere either directly by natural and anthropogenic sources or by oxidation processes in the atmosphere. The most prominent precursor gas is probably sulfur dioxide (SO2). It is the precursor for particulate sulfates, such as sulfuric acid (H2SO4) or ammonium sulfate [(NH4)2S04]. Sulfur dioxide is directly emitted by natural sources (e.g., volcano emptions). Anthropogenic sources in industrial regions are mostly associated with combustion processes (e.g., coal combustion). Additional SO2 is derived from oxidation processes of dimethyl sulfide (DMS) over the oceans. Estimations of the global sulfur emissions from these sources are listed in Table 3. 

The first recognized type of air pollution was that typified by high concentrations of sulfur compounds (SOj and sulfates) and particles, resulting from combustion of coal and high-sulfur-containing fuels. Cities with this characteristic type of air pollution are often in cold climates where electric power generation and domestic heating are major sources of emissions. 

Man-made sources The burning of coal and oil accounted for virtually all the sulfur oxides emitted from man-made sources in the eastern U.S., about 30.6 million tonnes (calculated as sulfate) in 1980. (Table 2). (Emissions are estimated from the sulfur content of each type of fuel and the amount of fuel consumed.) Electric utilities contributed 71% of the total SO2, with the majority of emissions coming from coal-fired power plants. The remainder came chiefly from industrial, commercial and residential combustion transportation smelters and industrial processes. An additional 2.1 million tonnes entered the U.S. from Canada, principally emissions from metal smelters,- and 1.2 million tonnes entered the region from the western U.S. ... 

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