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TOPICAL REVIEW: MUTAGENICITY AND CARCINOGENICITY OF AIR
Citation:
CLAXTON, L. D. TOPICAL REVIEW: MUTAGENICITY AND CARCINOGENICITY OF AIR. Presented at Environmental Mutagen Society 38th Annual Meeting, Atlanta, GA, October 20 - 24, 2007.
Impact/Purpose:
This presentation reviews the literature on the genotoxicity of outdoor and indoor air.
Description:
Although both outdoor and indoor airs provide exposure to mutagens and carcinogens, this review shows that the level of hazard is highly variable. Outdoor air was first shown to be carcinogenic in 1942 and mutagenic in 1975; and studies examining the genotoxicity of indoor air soon followed. However, many questions remain. Interestingly, conclusions from many prior research studies are consistently overlooked. This presentation reviews the literature on the genotoxicity of outdoor and indoor air. Urban air was carcinogenic in most of the reports involving rodents and in most bacterial and plant studies for mutagenicity. Carcinogenic activity is due primarily to PAHs, nitroarenes, and other aromatic compounds. Atmospheric conditions, along with the levels and types of pollutants, contributed to the variations in carcinogenic and mutagenic activity of air from different metropolitan areas. Indoor air was consistently mutagenic when cigarette smoking, coal or biomass combustion, and cooking fumes were present. By analyzing matched indoor and outdoor PAH concentrations, one sees a strong relationship (r2=0.91, p<0.001) indicating the impact of outdoor air on indoor air. However, the impact of certain indoor air sources (e.g., cigarette smoking) can modify this relationship. The majority of the literature for both outdoor air and indoor air was with the Salmonella assay (~50-60%). Air sheds contain similar types and classes of mutagens; however, the levels of these compounds vary considerably among air sheds. Combustion emissions were associated with much of the mutagenicity and carcinogenicity of urban air. Most outdoor air studies focused on the particulate fraction; thus, additional work is needed on the volatile and semi-volatile fractions, metals, and atmospheric transformation. Smaller particles have greater percentages of extractable organic material and are more mutagenic than larger particles. Only a few (<25) of hundreds of genotoxic compounds are routinely monitored, emphasizing the value of coupling bioassay with chemistry in the monitoring of air for carcinogenic and mutagenic activities and compounds.