Size Distribution of Sulfate Aerosols in the Ambient Air

Abstract

Size distributions of sulfate aerosol in Cincinnati and Chicago show MMD’s of 0.4 and 0.3μ. Eighty to 90 percent of the sulfate measured was in the respirable size range (below 3.5 mμ), whereas about 50 percent of the total aerosol was in the respirable range. Two sampling trains were used: one, a cascade impactor followed by a filter, gave seven stages of size and sampled at one cfm. The other, a cyclone-type sampler followed by a filter, sampled at 40 cfm. The smaller samples were analyzed nephelometrically and the larger, turbidimetrically.