Complex Mixtures of Urban Air Pollutants: Identification and Comparative Assessment of Mutagenic and Tumorigenic Chemicals and Emission Sources

摘要

Advances in the cancer risk assessment of complex mixtures of urban air pollutants requires the development of new methods in predicting human risk. Current research is focusing on the identification and source apportionment of airborne carcinogens and the development of new exposure, dosimetry and extrapolation methods which can be applied to complex mixture problems. Research on the identification of the genotoxic compounds in urban air and particularly on the polar mutagenic compounds, many of which appear to be nitrated and or oxygenated aromatic compounds, is advancing with the use of micromutagenesis methods coupled to analytical fractionation and new chemical characterization methods. Source apportionment of the mutagenic activity observed in urban air shows that the small area combustion sources, vehicles and residential heating, are the major contributors to the ambient mutagenicity of the aerosol fraction. The potential hazard and sources of the gaseous emissions appear to be significantly increased by atmospheric transformation by ozone and nitrogen oxides. Studies are being conducted with current environmental combustion emission sources and urban aerosol samples as well as with emission sources for which human lung cancer data and human tissues are available for comparative assessment.