A study of twelve southern California communities with differing levels and types of air pollution - I. Prevalence of respiratory morbidity

To study possible chronic respiratory effects of air pollutants, we Initiat ed a 10-yr prospective cohort study of Southern California children, with a study design focused on four pollutants: ozone, particulate matter, acids, and nitrogen dioxide (NO2), Twelve demographically similar communities wer e selected on the basis of historic monitoring information to represent ext remes of exposure to one or more pollutants, in each community, about 150 p ublic school students in grade 4, 75 in grade 7, and 75 in grade 10 were en rolled through their classrooms. informed consent and written responses to surveys about students' lifetime residential histories, historic and curren t health status, residential characteristics, and physical activity were ob tained with the help of the parents. In the first testing season, 3,676 stu dents returned questionnaires. We confirmed associations previously reporte d between respiratory morbidity prevalence and the presence of personal, de mographic, and residential risk factors. Rates of respiratory illness were higher for males, those living in houses with pets, pests, mildew, and wate r damage, those whose parents had asthma, and those living in houses with s mokers. Wheeze prevalence was positively associated with levels of both aci d (odds ratio [OR] = 1.45; 95% confidence interval [CI], 1.14-1.83) and NO2 (OR = 1.54; 95% CI, 1.08-2.19) in boys. We conclude, based on this cross-s ectional assessment: of questionnaire responses, that current levels of amb ient air pollution in Southern California may be associated with effects on schoolchildren's respiratory morbidity as assessed by questionnaire.