Oxygen and Ozone

This chapter discusses the physical and chemical properties of oxygen (O) and ozone (O3). Oxygen concentration in air is essentially constant in the overall environment, and toxic effects have not been observed. Toxicity caused by oxygen is dependent on its duration of exposure and chemical activity. Oxygen exposure at elevated atmospheric pressures causes central nervous system abnormalities ranging from muscular twitching, tunnel vision, and aphasia to grand mal seizures. Premature infants are more sensitive to increased oxygen pressures than adults. Exposure to increased oxygen levels for prolonged periods is accompanied by a risk of developing a chronic respiratory condition. Experimental studies utilizing animal models, principally rodents, have demonstrated that acute, high level exposure to ozone results in mortality through the induction of severe pulmonary edema. Ozone has relatively mild irritant effects on the eyes and skin at the current levels of exposures, but these effects are transient without permanent residua.