ABSTRACT
This chapter presents the toxicology of oxidants and free radicals, and focuses primarily on oxygen and ozone. The laboratory animal studies to determine genotoxicity and carcinogenicity following ozone exposure have been inconclusive, particularly at the lower ozone concentrations. Molecular oxygen addition into polyunsaturated fatty acids initiates a chain reaction in which certain reactive oxidant species radical species are formed. Oxidative stress reflects the morphological consequences of a mismatch between the rate of formation of free radicals and the capacity of the cell to transform them to less toxic species. Injury and mortality after exposure to 100% oxygen can be diminished by surfactants that may operate by mechanisms other than the responsible for surface tension effects. A review of the regulation of various antioxidant enzymes after different types of oxidant stresses to the lung suggests that more than one enzyme is involved.
