Abstract: | A study was made on the induction of sister-chromatid exchanges (SCE) in cultured Chinese hamster V79 cells exposed to the photochemical reaction products of toluene plus NO2 in the gas phase. The photochemical reaction products of toluene plus NO2 were obtained by photochemical reaction of a toluene--NO2/dry air system in a photochemical smog chamber and then exposed to cultured cells for 2 h using a system for in vitro gas exposure. SCEs were induced at all concentrations of the photochemical reaction products employed in the present study, and the highest SCE frequency observed for the highest concentration tested for each component was 3.6 times higher than that of the control. Cytogenotoxicity which was evaluated with induced-SCEs of the photochemical reaction products of toluene plus NO2 was much the same as that of the previously reported photochemical reaction products of propylene plus NO2 (Shiraishi and Bandow, 1985), but was considerably stronger than that of typical gaseous air pollutants such as NO2 alone and O3 alone. |