Ozone Health Effects and Emerging Issues in Relation to Standards Setting

Abstract

Our current knowledge of o3 exposure and health effects is growing rapidly. Transient respiratory function effects accumulate throughout an exposure day, and ambient exposures have broad daily peaks. 03 exposures also produce changes in airway inflammation and permeability. Healthy adults engaged for ~ 1/2 hr in outdoor exercise show greater responses than those observed in chamber studies involving 1 or 2 hr of exposure, indicating potentiation of the 03 response by other environmental exposures. Acute animal studies show biochemical and structural responses to 03 are potentiated by co-exposure to N02 and H2SO4 Chronic animal studies show that 03 effects on lung structure accumulate, and several recent epidemiological studies suggest that cumulative functional effects are occurring in people. Recent research has also shown: 1) a seasonal variation in functional responsiveness in humans; 2) that a seasonal pattern of daily exposure in monkeys produces greater changes in the lung than a continuous pattern of daily exposures at the same concentration; and 3) that transient exposures produce persistent responses.