We conducted a study in three representative areas of Beijing to determine respiratory health effects of indoor and outdoor air pollution. In August 1986, we measured the lung function of 1,440 adults who were 40-69 y of age and who had never smoked. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1.0) were adjusted for height, sex, and age. Outdoor ambient air pollution measurements from the World Health Organization Global Air Pollution Monitoring Station were very different in the three study areas; the annual mean concentrations of sulfur dioxide (SO2) in residential, suburban, and industrial areas were 128, 18, and 57 micrograms/m3, respectively, and annual mean concentrations of total suspended particulate matter (TSPM) were 389, 261, and 449 micrograms/m3, respectively. Coal was most frequently used for domestic heating in the residential (92%) and suburban (96%) areas compared with the industrial area (17%). Heating with coal was associated with a reduced FEV1.0 (-91 +/- 36 ml) and FVC (-84 +/- 41 ml). Living in the residential area was associated with an additional reduction in FEV1.0 (-69 +/- 34 ml) and FVC (-257 +/- 37 ml). After we adjusted for age, height, and sex, an inverse linear association was found between In outdoor SO2 (or TSPM) concentration and FEV1.0 and FVC in subjects who had and had not used coal stove heating. Regression analysis results showed that a per-unit increase in In SO2 (TSPM) concentration (microgram/m3) could result in a 35.6 (131.4) ml reduction in FEV1.0 and a 142.2 (478.7) ml reduction in FVC.(ABSTRACT TRUNCATED AT 250 WORDS)