Mutagenic activity of total and particle-sized fractions of urban particulate matter

Total or inhalable (PM(10)) particulate matter is monitored as a quality air criteria. Airborne particles deposit onto the differently sensitive biological tissues of the respiratory tract depending on their size. So it is very important to know the mutagenic activity (index of potential carcinogenicity) of the substances carried onto the diverse sized fractions of urban particulate matter, especially those under 1 mu m in diameter. The mutagenicity of total and sized fractions of urban particulate matter of Bologna (Italy), representative of a medium size town surrounded by small and medium industries, was investigated using the plate incorporation test on Salmonella typhimurium. There is no correlation between total and/or coarse particle matter concentration in air and mutagenic activity, the correlation increases as the particle size decreases; moreover, the finer the particulate matter, the greater the mutagenicity is. That is of great concern for health risk estimation. Total or inhalable (PM(10)) particulate matter is not representative of air quality, at least with regard to the mutagenicity.