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ASSESSMENT OF NATIONAL AND REGIONAL ACID DEPOSITION PRECURSOR EMISSION TRENDS
Citation:
Wilson, Jr., J., E. Pechan, AND K. Graves. ASSESSMENT OF NATIONAL AND REGIONAL ACID DEPOSITION PRECURSOR EMISSION TRENDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/8-89/042.
Description:
The report gives results of an analysis of national and regional acid deposition precursor emission trends, involving SOx, NOx, and VOCs. While the focus is on emissions during 1980-1985, comparisons are made (for perspective) with emission trends for 1940-1980. Study methods integrated data from the U.S. EPA's national emission trends reports, state and regional activity indicators, and plantlevel data for electric utilities and copper smelters. For 1980-1985, all three pollutants showed both annual declines and increases. The most pronounced decline was for SOx, with a net decrease of almost 11% from 1980 to 1985, most of which occurredbetween 1980 and 1982. National VOC emissions declined 7% from 1980 to 1985, but the change in NOx emissions was insignificant compared with potential uncertainties in the analysis methods. For a longer term, emission trends can be divided into three periods: (1) 1940 to the mid-1970s, when emissions increased in proportion tofuel use and the GNP; (2) the late 1970s to the early 1980s, the "emissions control era," when Clean Air Act programs produced a downward trend for all pollutants except NOx as the economy continued growing; and (3) since 1980, when relationshipsbetween emissions and the economy, fuel use, and regulations are making it more difficult to predict emissions in future years.