Respiratory questionnaires (ATS-DLD-78) were administered to 5557 adult women in a rural area of Western Pennsylvania to evaluate the health effects of air pollution resulting from coal combustion. Air pollution data were derived from 17 air quality monitor sites and stratified to define low, medium, and high pollution areas. The means of 4 yr (1975-1978) annual averages for sulfur dioxide in each strata were 62, 66, and 99 micrograms/m3, respectively. Total suspended particulates were not tested as a risk factor because they reflected air pollution from sources other than coal combustion (e.g., agricultural, road dusts). Risks of respiratory symptoms were evaluated in a multiple logistic model that adjusted for several potential confounding factors. The risk of "wheeze most days or nights" in nonsmokers residing in the high and medium pollution areas was 1.58 and 1.26 (P = .02), respectively, relative to residents in the low pollution area. In the subset of residents who had lived in the same location for at least 5 yr, relative risks increased to 1.95 and 1.40 (P less than .01), respectively. An increased risk of grade 3 dyspnea in nonsmokers was associated with sulfur dioxide but did not achieve statistical significance (P = .11), and there was no association of cough or phlegm and air pollution in nonsmokers. Cigarette smoking characteristics were the major determinant of respiratory symptoms in smokers, and no independent association of air pollution was found. This study suggests that wheezing may be associated with ambient exposure to sulfur dioxide in nonsmokers, but no effect of sulfur dioxide on cigarette smokers was observed.(ABSTRACT TRUNCATED AT 250 WORDS)