We conducted an epidemiological study to investigate the association between exposure to automobile exhaust and respiratory health. We selected 3 zones from two geographically different areas in Tokyo on the basis of expected exposure levels: (1) within 20 m from the side of major roads with heavy traffic, (2) between 20 and 150 m from the side of the same road, and (3) a residential district of suburban Tokyo. The subjects of the study were female adults aged 30-59 y. A cross-sectional study of respiratory symptoms and repeated pulmonary function testing were also performed in each zone. The results suggested that exposure to automobile exhaust may be associated with respiratory symptoms. Nevertheless, repeated pulmonary function testing did not reveal any consistent differences. Investigators should conduct additional follow-up studies to investigate the decline of pulmonary functions with age.