Genotoxicity of urban air particulate matter: Correlations between mutagenicity data, airborne micropollutants, and meteorological parameters

The mutagenicity of airborne particulate matter was monitored at a site representative of the high traffic density of the city of Rome. Inhalable (less than 10 μm) particles were collected every other day with a high‐volume sampler from November 1990 to April 1991. Mutagenicity of particle extracts was evaluated by the microsuspension procedure with Salmonella typhimurium strain TA98. Mutagenic activities of particle extracts displayed a fourfold variation during the period of sampling, with the lowest values in April (about 600 induced revertants mg‐1), and the highest in February (about 2500 revertants mg‐1). Multivariate statistical analyses on the interrelationships between mutagenicity, micropollutants levels and meteorological parameters highlighted a close inverse relationship between air mutagenicity and ambient temperature. Lower temperatures determined both an increased content of organic matter on air particles, and an increased mutagenicity (on a weight basis) of particle extracts, which was associated with a relative enrichment of the more volatile PAHs.