An analysis of the fate of lead in the Los Angeles Basin is used to evaluate an emissions to air quality model for automotive exhaust particulates. The dispersion model is then applied to projecting the annual average sulfate air quality impact of direct sulfuric acid mist emissions from oxidation catalyst-equipped cars of the 1975 model type. Estimates are given of the incremental sulfate contributions from three model years of oxidation catalyst-equipped cars burning a relatively low sulfur gasoline, and from roughly ten model years of 1975-type autos burning gasoline of sulfur content equal to that of the entire 1974 Southern California gasoline pool. In the latter case, sulfate concentrations in portions of downtown Los Angeles in 1985 could be elevated by roughly two thirds above present average sulfate values
