Asthma related to occupational and ambient air pollutants in nonsmokers.

We attempted to determine the association between occupational and air pollutant exposure with the development of adult asthma through the analysis of a standardized respiratory questionnaire administered to a cohort of 3914 nonsmoking adults in 1977 and again in 1987. Ambient air pollution concentrations were estimated over a 20-year period using monthly interpolations from fixed-site monitoring stations applied to zip code locations by month of residence and work site. Second-hand smoke exposure was significantly associated with the development of asthma (related risk [RR] = 1.45, confidence interval [CI] = 1.21 to 1.75). Airways obstructive disease before age 16 was related to a marked increased risk (RR = 4.24, CI = 4.03 to 4.45). An increased risk of asthma was significantly associated with increased ambient concentrations of ozone exposure in men (RR = 3.12, CI = 1.61 to 5.85).