The proposed research effort will complete and analyze six data sets collected during a multidisciplinary longitudinal study of air pollution and respiratory health that began in 1974. Initial cohorts of 14,357 children and 8,842 adults were enrolled in six U.S. cities and have been followed for twelve years. A second cohort of 6,288 children was enrolled between 1983 and 1986 and followed for two years. Detailed ambient air pollution measurements have been collected over a twelve year period in each community. In the second cohort of children, a subset of 1,800 children was identified for participation in an indoor air pollution study involving four weeks of measurement in each home and in a nine to twelve month diary study of daily respiratory symptoms. All of these studies will be completed by the fall of 1989. Issues to be investigated in these data include: A) In children, to describe age-related changes in pulmonary function levels and respiratory morbidity that occur between 6 and 18 years of age, and the effects of air pollution exposures on these changes. B) In the second age-matched sample of children, to determine whether reductions in air pollution concentrations have led to improved respiratory health. C) In adults, to describe the effects of air pollutants on changes over 12 years in pulmonary function and respiratory morbidity. D) In adults, to relate mortality during the twelve-year follow-up to baseline pulmonary function levels, respiratory morbidity, and air pollution exposures. E) In children, to relate short-term changes in pulmonary function and respiratory symptom reporting to daily fluctuations in air quality. F) In children, to develop individual indices of total exposure to inhalable particles and NO2 from data obtained in the indoor monitoring studies and to investigate relations between these exposure indices and respiratory health. Vital status and current address records will be maintained for the original samples of children and adults to retain the cohorts as a resource for future studies.