An epidemiologic study of chronic respiratory diseases was carried out in 3021 adults Living in areas with different levels of particulate air pollution. Stratified analysis and multiple logistic regression were used in analysing the data. There were positive association between particulate air pollution and prevalence rates of chronic cough, phlegm production, dyspnea, chronic bronchitis and pulmonary emphysema. Increase of the risk of these diseases symptoms were observed in the aged, smokers in high poll...