Separation of anthropogenic and natural emissions of particulate heavy metals in the western Mediterranean atmosphere

Abstract

Measurements of atmospheric particulate matter often include both natural and anthropogenic aerosols. The method proposed here allows the two contributions to be separated, and then, to be estimated. Sampling was carried out at Cape Ferrat, on the southeastern coast of France, during 1986 and 1987. The concentrations of Pb, Cu, Zn and Cd were measured using flameless atomic absorption spectrophotometry. The concentration data allowed us to establish, for each metal, an experimental probability density function, which was numerically analyzed. The numerical process is described in detail. The results show a good agreement between the calculated natural background aerosol at Cape Ferrat and natural concentration levels measured in several remote locations. Differences are explainable by the nature of the environment. Anthropogenic emissions are very high compared with natural inputs, because most of the airborne heavy metals in the western Mediterranean arise from human activities.