Air quality and pediatric emergency room visits for asthma in Atlanta, Georgia

Pediatric emergency room visits for asthma were studied in relation to air quality indices in a spatio-temporal investigation of approximately 130,000 visits (similar to 6,000 for asthma) to the major emergency care centers i n Atlanta, Georgia, during the summers of 1993-1995, Generalized estimating equations, logistic regression, and Bayesian models were fitted to the dat a. in logistic regression models comparing estimated exposures of asthma ca ses with those of the nonasthma patients, controlling for temporal and demo graphic covariates and using residential zip code to link patients to spati ally resolved ozone levels, the estimated relative risk per 20 parts per bi llion (ppb) increase in the maximum 8-hour ozone level was 1.04 (p < 0.05). The estimated relative risk for particulate matter less than or equal to 1 0 mu m in aerodynamic diameter (PM10) was 1.04 per 15 mu g/m(3) (p < 0.05). Exposure-response trends (p < 0.01) were observed for ozone (>100 ppb vs. <50 ppb: odds ratio = 1.23, p = 0.003) and PM10 (>60 mu g/m(3) vs. <20 mu g /m(3): odds ratio = 1.26, p = 0.004). In models with ozone and PM10, both t erms became nonsignificant because of collinearity of the variables (r = 0. 75), The other analytical approaches yielded consistent findings. This stud y supports accumulating evidence regarding the relation of air pollution to childhood asthma exacerbation.