POLYNUCLEAR AROMATIC-COMPOUNDS AND GENOTOXICITY IN PARTICULATE AND VAPOR-PHASES OF AMBIENT AIR - EFFECT OF TRAFFIC, SEASON, AND METEOROLOGICAL CONDITIONS

High-volume samples of ambient air were collected by glass-fiber filter (particulate) and XAD-2 resin (vapor) from three locations in Finland: two cities and a rural area. Samples were analyzed for polynuclear aromatic hydrocarbons (PAH) and selected other polynuclear compounds. Genotoxicity of the samples was assayed in the Ames Salmonella/microsome test and sister chromatid exchange assay before and after fractionation into four fractions of increasing polarity. The rural samples showed minimal or no genotoxic activity, whereas the urban sites not only the particulate-phase but also the vapor-phase samples were mutagenic. the genotoxity was mainly associated with the most polar fractions of both phases. In the urban air samples collected in winter, a considerable part of the mutagenicity detected in the Ames test was due to NO//2-substituted compounds. Traffic is suggested to be the major determinant for the genotoxic activity in the ambient air.