Photochemical formation of mutagenic compounds from alkenes and ozone or nitrogen dioxide.

In order to investigate the possible formation of mutagenic compounds from alkenes emitted in ambient air, laboratory experiments were performed with Salmonella typhimurium strain TA100 in a small-scale flow-through exposure system. The reaction time for mixtures of alkenes with ozone or nitrogen dioxide was 40 minutes, and the exposure time for bacteria was 6 hours. Ozone gave rise to a small mutagenic effect in combination with 1,3-butadiene or vinyl chloride, with and without ultraviolet (UV) irradiation, but not in combination with ethene or propene. Nitrogen dioxide gave rise to a mutagenic effect in combination with propene, 1,3-butadiene, or vinyl chloride, but only after UV irradiation. The mutagenic activity was highest with butadiene and seemed to be dose-related to the concentration of nitrogen dioxide. Nitrogen dioxide with ethene did not produce a mutagenic effect. A mixture of ethene, propene, and butadiene, tested with ozone or nitrogen dioxide with UV irradiation, did not potentiate each other's mutagenic effect.