Community Health and Environmental Surveillance Systems (CHESS) studies provide dose-response information relating short- and long-term air pollution exposures to adverse health effects. This report presents results of studies in CHESS communities in New York and the Salt Lake Basin during 1970-1971. Studies in Idaho-Montana, Chicago, and Cincinnati, employing health indicators similar to those used in CHESS, are also included. Attention is focused on effects of sulfur oxides, but the relative contribution of various pollutants, especially sulfur dioxide, particulates, and suspended sulfates, is considered. Health indicators of long-term pollution effects included acute and chronic respiratory illness and ventilatory function. Indicators of short-term effects were cardiopulmonary symptoms and asthma. Threshold estimates for the pollutants considered support existing National Primary Air Quality Standards for long-term exposures.