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TRENDS OF SEASONAL HAZINESS AND SULFUR EMISSIONS OVER THE EASTERN U.S.
Citation:
Husar, R. TRENDS OF SEASONAL HAZINESS AND SULFUR EMISSIONS OVER THE EASTERN U.S. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/3-89/062 (NTIS PB89220511), 1989.
Description:
Reduction in visual range in the eastern U.S. is caused largely by sulfate particles. Therefore, it is expected that the spatial distribution and temporal trend of man-made haziness will, to some extent, correspond to the spatial-temporal pattern of sulfur emissions. The purpose of this study is to examine the sulfur emission-haze relationship using regionally and seasonally disaggregated SO2 emissions and visual range data. Across much of the Northeast the wintertime haziness has been either declining or slightly increasing over the past three decades. On the other hand, the summertime haziness has been generally increasing in all areas of the eastern U.S. The monthly sulfur emissions for individual states were reconstructed using yearly emission trends and seasonal emission rates. Before 1970 winter emissions were greater but since the 1970's the summer emissions have become comparable in magnitude. Comparisons of sulfur emissions and haziness are shown in Figure 1. In the northeast there is a general correspondence in the trends: a decline in the winter season and an increase during the summer. In the southeastern states there is also a close correspondence between emissions and haze trends, particularly in the summer season. These relationships may be used as a first indication of how visibility might change with changes in SO2 emissions.