This report is in response to Section 403(a)(1) of the Clean Air Act as Amended August 1977. The report covers: (1) a review of the physical and chemical characteristics of airborne particles (source, composition, and sampling site as related to size); (2) a review of the effects of particulate matter on public welfare (ecological, materials, atmospheric, aesthetic); (3) the status of human exposure to airborne particles as related to source; and (4) a review of the effects of airborne particles on human health (lung deposition, chemical composition, interactions, and potentiating conditions). Although there is a wide divergence of opinion among experts and scientific groups with respect to the issues of particulates (cf. Appendix A), the following can be concluded from the available information: (1) High levels of airborne particles have been associated with episodes of high pollution during the past, especially in the United Kingdom and the United States. (2) Although pollution levels have declined in many U.S. localities in recent decades, there is still need for improvement in several of our cities. (3) Additional research is needed to improve the scientific basis for future airborne particle standards as outlined by EPA (cf. Dr. Cortesi in the Culver Pilot Study of Particulate Matter).

"Feb 79." Includes bibliographical references. "Notice: This document has been reproduced from the best copy furnished us by the sponsoring agency. Although it is recognized that certain portions are illegible, it is being released in the interest of making available as much information as possible." "EPA 600/9-79-006." "PB82-189556." Photocopy

This report is in response to section 403(a)(1) of the Clean Air Act as Amended August 1977. This report covers: 1) a review of the physical and chemical characteristics of airborne particles (source, composition, and sampling site as related to size) ; 2) a review of the effects of particluate matter on public welfare (ecological, materials, atmospheric, aesthetic) ; 3) the status of human exposure to airborne particles as related to source ; 4) a review of the effects of airborne particles on human health (lung deposition, chemical composition, interactions, and potentiating conditions). 1. Executive summary -- 2. Introduction -- 3. Characteristics of airborne particles -- 4. Aerosols: sources and concentrations -- 5. Effects of airborne particles on human health -- 6. Effects of particulate matter on public welfare -- 7. References.