Several investigators in diverse geographical locations have detected airborne mutagens with the Ames' Salmonella typhimurium bioassay. Yet to be established is the aerodynamic diameter of the mutagen-containing particles. To study this matter, an Andersen 2000 sampler was used to collect size-fractionated samples in Durham, NC. The samples were extracted and concentrated, the masses were determined, and the mutagenic activities were bioassayed. Initial studies were designed to establish a protocol suitable for routine air sampling. A sufficient sample quantity was obtained by operating four of the Andersen samplers simultaneously over a 5-7 day interval. The results of 10 weekly samplings indicated that most of the deposited mass, and most of the mutagenic activity, occurred in the fractions containing the small (less than 2 micrometer) particles. Selected extracts, positive for mutagenicity, were tested for the presence of electrophiles by reaction with nitrobenzylpyridine (a chemical nucleophile) or by reaction with electrons provided in the course of dc polarographic analysis. These chemical tests verified the presence of direct-acting alkylating agents in extracts of deposited aerosols.

"EPA-600/3-79-032"--Cover. "April 1979"--Cover. "College of Natural and Agricultural Sciences University of California, Riverside"--T.p. EPA contract no. DA-8-1578J. Project officer: Lester L. Spiller Atmospheric Chemistry and Physics Division Environmental Sciences Research Laboratory"--T.p. Includes bibliographical references.