Application of the Ultramicro Forward-Mutation Assay to the Monitoring of Indoor and Outdoor Air Mutagenicity-Examples of Chengdu City and Tokyo

Various chemicals are emitted into the air from factories, offices, incinerators, and vehicles by industrial activity (Alfhei & Mψller, 1981; Mψller et al, 1982; Watanabe & Hirayama, 1997). In addition, indoor air is polluted by chemicals used or exhausted intentionally or unintentionally during heating (use of town gas and fossil fuel), cooking, smoking and building materials (Endo et al, 2000; Koyano et al, 1999; Takagi et al, 1997). People are concerned about the health impacts of the hazardous chemicals contained in those materials. The carcinogens and mutagens detected in air can be classified into two groups: particulate matter and gas/vapor matter. Regarding particulate matter, various substances including inorganic ones such as heavy metals and organic compounds such as polycyclic aromatic hydrocarbons are detected. Such substances and compounds include polycyclic aromatic hydrocarbons (PAHs) like benzo[a]pyrene, which is now attracting attention as a carcinogenic/mutagenic substance, and dinitropyrene, which shows extremely high mutagenicity for Salmonella TA98 strain (Watanabe & Hirayama, 1997). It is widely known that PAHs are formed during the incomplete combustion of organic matter (Somenath & Wilson, 1992). PAHs are also formed when fossil fuel is burned by industry and in daily life and so the health hazards of PAHs contained in the environment cannot be avoided. People spend 80 to 90% of their time indoors, and especially infants, elderly people and sick people with a weak immune system spend even longer hours indoors. Therefore, it is important to keep the indoor environment clean because human health is greatly influenced by the environment. However, there have been few studies on the mutagenicity of indoor air because the amount of such substances that can be sampled is limited. A new mutagenicity test that is more sensitive than the existing widely-usedAmes method: “plate incorporation method” and “preincubation method” needs to be developed. We studied use of the ultramicro forward mutation Assay,