Volatile organic compounds (VOCs) and air mutagenicity: Results of one year monitoring at an urban site

The concentrations of four volatile organic compounds (VOCs: benzene, toluene, ethylbenzene and xylenes) and the levels of inhalable (< 10 μm) airborne particles were monitored during 1 year at a site with intense vehicular traffic in the city of Rome. VOCs as well as airborne particulate matter were sampled every alternate day and pooled in fortnightly samples representative of the first and second half of each month. Some meteorological parameters (mean temperature, heliophany, air pressure and relative humidity) were concurrently recorded. Air particulate extracts were tested for mutagenicity in the Salmonella reversion system with tester strain TA98. Air mutagenicity levels were compared to air concentrations of benzene and alkylbenzenes, putative indicators of vehicular traffic, in order to elucidate their interrelationships. The results of multivariate statistical analyses show that seasonal variations in air mutagenicity are mainly dependent on the increased content of organic matter in airborne particles, possibly resulting from the increased deposition rate of semivolatile compounds with low ambient temperature. A weaker association was observed between air mutagenicity level and VOCs concentrations.