Evaluation of influences of air-borne particulates by molecular and cellular biological methods

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Air-borne particulates are major air pollutants in these decades. Especially, the particulate smaller than 2.5 μm diameter (PM2.5) is originated from diesel exhaust gas and considered to be a harmful substance to human health. Concentration of the PM2.5 in air has been shown positive correlation to induction of lung cancer. We obtained the air-borne particulates in Osaka, Higashi-osaka and Sakai Cities and analyzed their distribution of the particulate sizes and chemical composition. We also measured mutagenicity and endocrine disturbing ability of the particulates by bioassays and molecular biological methods.In Osaka and Higashi-osaka Cities (urban area), the distribution of the particulate size showed two peaks that were divided at approximately 2μm diameter. The mutagenicity and endocrine-disturbing activity were agree to the distribution of the small size peak (smaller than 2 μm diameter). In Sakai City (residential area), the endocrine-disturbing activity is stronger in the winter particulate sample than the summer one. The concentration of the particulate in air has gradually decreased year by year.As a result of molecular experiment, 3-nitrobenzanthrone(NBA), a strong mutagen contained in the particulate, caused G:C to T:A base change mutations in human and Escherichia coli cells. The NBA adducts in DNA was miscoded by the error-prone DNA polymerase V (umuDC), and they induced mutations.These results are valuable for prevention of lung cancer and for risk estimation of human population of the air-borne particulates.