Effect of air pollution on chronic respiratory disease in the New York city metropolitan area, 1972.

The effect of air pollution on chronic respiratory diseases (CRD) was examined in a study in the New York metropolitan area in 1972. Four study communities, sites A, B, C and D, were selected for the similarity of socioeconomic and demographic characteristics. Historically, these communities represented an increasing gradient of air pollution levels. However, after air quality improvement in the metropolitan area, Site A had only slightly lower pollution levels than sites B, C and D. In the examination of chronic respiratory symptoms, study hypotheses were established to correspond with historical levels of air pollution. The study population was drawn from parents of children attending elementary school in each site. Information was obtained by means of a questionnaire modified from the 1966 BMRC questionnaire. The analysis was based on 5416 white long-term residents without occupational exposure to irritant dust and fumes. Confounding factors, including smoking status, age, level of education of head-of-household and crowding within the home, were examined. Smoking was found to be the most important factor in determining the level of severity of CRD. The effect of air pollution showed differential patterns among the smokers and nonsmokers. Among the smokers, no air pollution effect was observed. However, among nonsmokers, a statistically significant difference was observed among females. Further, among male nonsmokers a similar pattern was observed, but the effect was not statistically significant. Other possible factors that could contribute to the difference are discussed.