The report was prepared, at the request of the Environmental Protection Agency by the Committee on Indoor Pollutants. It outlines the scope of the problems regarding indoor pollutants and discusses their sources, their effects on human health and welfare, the technologies available for their control or abatement, and concerns about the effects of energy-conservation strategies on indoor concentrations of pollutants. It approaches the subject of indoor pollution from three viewpoints: 1. Physical factors, such as indoor pollutant sources and concentrations. 2. Biomedical evidence on the effects of several pollutants found in the indoor environment. 3. Engineering, air-handling and cleaning systems, and other control options for reducing indoor exposures to pollutants.