Bioassay of complex mixtures of indoor air pollutants

The development of short-term genetic bioassays has made it possible to conduct mutagenicity studies on complex mixtures of indoor air pollutants. Although most of the studies have used the standard S. typhimurium/microsome reversion assay developed by Ames et al. (1975), the development of microsuspension mutagenesis methods (see Methods 18 and 19, this volume) has facilitated wider use of bioassays in indoor air pollution studies. It is clear from the studies reviewed here that environmental tobacco smoke is the major source of mutagens indoors. Other sources which produce significant, but much smaller, increases in indoor air mutagenicity include outdoor air and other indoor combustion sources (e.g., cooking, kerosene heaters and open fireplaces burning wood). These studies have been based on measurement of the bacterial mutagenicity of extracts from particulate matter. A limited number of reports, however, indicate that volatile and semi-volatile constituents of indoor air may also be mutagenic and deserve further study.