This report presents the results of a wind tunnel model study to determine the ground level SO2 concentrations in the Clairton Area of Allegheny County, produced by emissions from stationary sources within the area. The study was designed to provide data under flow conditions which correspond roughly to those which prevailed during an air pollution episode at Liberty Burough, Clairton in January 1973. The inventory of emission sources used in the tests correspond to the estimated 1973 full-scale inventory for 49 sources which were located within the confines of the modeled area. The test program included flow visualization studies and quantitative measurements of ground-level concentrations of a tracer gas from which full-scale SO2 concentrations could be calculated. The concentration level measurements were performed for four wind directions. At each wind direction, three wind speeds were studied with neutrally stable flow, and for one of these a temperature inversion condition was also tested. The report presents details of the model scaling laws, the test facilities, the model, test procedures, and the experimental results.