Information on respiratory health was collected from 3709 Chinese adults in Beijing, Anqing City, and rural communities in Anqing Prefecture. Indoor PM10 and SO2 were measured in a random sample of selected households. Using logistic regression and controlling for important covariates (excluding PM10 and SO2) and familial intraclass correlation, highly significant differences were found between study areas in the prevalence of chronic cough, chronic phlegm, wheeze, shortness of breath, but not physician-diagnosed asthma. Generally, observed respiratory symptom prevalence was lowest in Anqing city, higher in rural Anqing, and highest in Beijing. Median indoor concentrations of PM10 were similar in Anqing City and rural Anqing, but much higher in Beijing. Median SO2 concentrations were similar in all areas Daily mortality during 1995 in Chongqing, China was analyzed for associations with daily ambient SO2 and PM2.5. A generalized additive model using robust Poisson regression was used to estimate the association of SO2 and PM2.5, with daily mortality (on the same day and at lags up to five days) adjusted for trend, season, temperature, humidity and day of the week. The relative risk of mortality associated with a 100 mug/m3 increase in SO2 was positive on all days and highest on the second (1.04, 95% CI: 1.00--1.09) and the third (1.04, 95% CI: 0.99--1.08) lag days. However, the associations between daily mortality and PM2.5 were negative and insignificant on all days A cross-sectional study was conducted to investigate paternal smoking and children's pulmonary function in rural communities of Anqing, China. Adjusting for important covariates and intraclass correlation, multiple linear region models were used to estimate the effect of paternal smoking on the pulmonary function of 1718 children aged 8 to 15 years whose mothers were never-smokers. When compared to children of never-smoking fathers, children of smoking fathers had smell, but detectable deficits in FEV1 (-36 ml, se = 20) and FVC (-37 ml, se = 22). When children of smoking fathers were subdivided into two subgroups: father smoked <30 cigarettes/day and ≥30 cigarettes/day, children whose fathers smoked ≥30 cigarettes/day had the largest deficits in both FEV1 (-79 ml, se = 30) and FVC (-71 ml, se = 34)