This award supports the Third International Conference on Carbonaceous Particles in the Atmosphere to be held at Berkeley, California, October 5-8, 1987. The Conference will be a forum for the presentation and discussion of research on several aspects of the chemistry of airborne black carbon (soot). Topics to be covered are measurement methodologies; the sources, transport, and sinks of particulate carbon in the atmosphere; catalytic and nucleating influences of black carbon; effects of carbon on radiative transfer, climate, and visibility; effects on materials; and biological and human health effects.