The Optical Properties of Particulate Elemental Carbon

Recent measurements of the absorption and scattering coefficients of tropospheric aerosols in both rural and urban areas have shown that these particles exhibit a significant (5 to 50% of the total extinction) amount of absorption in the visible spectrum. Elemental analyses have indicated that particulate elemental carbon is present and is the likely candidate to account for much of this observed absorption. Previous studies have demonstrated both experimentally and theoretically that a small amount of submicron carbon particles has a large effect on the absorption and scattering properties of tropospheric aerosols. This paper discusses the optical properties of particulate elemental carbon and illustrates the impact of these properties on the horizon brightness.