The mutagenicity of diesel-exhaust particle extracts collected under smog-chamber conditions using the Salmonella typhimurium test system.

This study was designed to detect the effect that different environmental conditions have upon diesel-exhaust organics. In this study, diesel exhaust was injected into the Calspan smog chamber under different conditions, and the resulting particles were collected upon Pallflex glass-fiber filters. After extraction from the particles with methylene chloride, the organics were solvent exchanged to dimethyl sulfoxide and tested in the Salmonella typhimurium plate-incorporation test. Results demonstrate that the irradiation of propylene, SO2, NO and NO2 produces ozone and a mutagenic moiety. Unless another mitigating factor (e.g., ozone) was present or formed, irradiation did not alter the mutagenic response of the organics. The production or injection of ozone into chamber tended to reduce the mutagenic response of the collected organics. In summary, this study demonstrates that ambient conditions can alter the mutagenic response of diesel-exhaust organics.