Ozone and ultraviolet light act as additive cocarcinogens to induce in vitro neoplastic transformation

Ozone, a major chemical oxidant in our environment, is an environmental air pollutant with putative carcinogenic action. Using in vitro transformation, we report for the first time that ozone (6 ppm for 10 min) acts in additive fashion with ultraviolet light (4 J/m2) to produce enhanced levels of transformation in hamster embryo cells and mouse C3H/10T-1/2 cells as compared to rats induced by each of the agents alone. The results underscore the hazard of ozone as a toxic pollutant which may have putative carcinogenic effects and interact with other environmental carcinogens.