The distribution and origin of mutagens in airborne particulates, detected by the salmonella/microsome assay in relation to levels of lead, vanadium and PAH.

At three stations in central Copenhagen, Denmark, samples of particulate matter were collected simultaneously with different contributions from automobile exhaust products. Samples were obtained at street level, 22 m above street level and within a hospital zone; 32 samples were analysed for levels of polycyclic aromatic hydrocarbons (PAH) and elements, as well as for mutagenicity towards S. typhimurium TA1538. Two classes of mutagens were quantified: a non-polar extract rich in PAH and, other promutagens, and a polar extract containing direct acting mutagens (not requiring microsomal activation). Covariances between lead and mutagenicity, and the varying distribution of the polar and non-polar mutagens at the stations, indicate that at all stations the mutagenicity of the non-polar extract is dominated by automobile exhaust products. The polar extract is relatively less influenced by primary traffic emissions; a considerable part of the activity of this extract is attributed to secondary emissions, transformed by atmospheric reactions, and primary emissions from stationary sources.