This report describes diffusion-model calculations of maximum 3-hour, 24-hour and average annual ground-level SO2 concentrations in Allegheny County produced by SO2 emissions from 107 major stationary sources and source complexes located within or adjacent to the county boundaries. The 1973 emissions data were used with concurrent meteorological observations from the Greater Pittsburgh and Allegheny County Airports to calculate the 1973 average annual SO2 ground-level maximums, as well as the 3-hour and 24-hour maximums for three selected 24-hour periods. These 1973 model concentrations were compared with observed air quality data from continuous monitoring sites to confirm the accuracy of the modeling techniques prior to performing the compliance case calculations. As an additional check on the diffusion-modeling techniques, a numerical mesoscale wind-field model was used to determine the effects of the elevated terrain along the Monongahela River on the trajectories of SO2 plumes originating from the Clairton Coke Works during moderate to strong southwesterly flow.

Prepared under contract by H.E. Cramer Company, Inc. for U.S. Environmental Protection Agency, Region III. Project Officer: Dr. Peter Finkelstein. "March 1975." "EPA 903/9-75-018."