Abstract
Risk assessments of diesel exhaust particles have been carried out by using animal experiment data. In the present study, the risk was estimated by using unit risk values from human epidemiological data. Unit risk value calculated by California EPA was applied to the diesel particle exposure level which was calculated from SPM values in every area of Japan. Following calculations of the averaged annual SPM value in each prefecture or big cities (SPMav), the regression coefficiency between SPM and elementary carbon concentration (R), the contributing rate of car exhaust particles to total atmospheric elementary carbon (C%), the contributing rate of diesel particles to total car exhaust particles (D%) and the averaged daily personal exposure rate in the environmental SPM level (P%) were obtained. All of these data regarding exposure were based on actual measurements and analytical data in literature. Unit risk×SPMav×R×C%×D%×P% was calculated by each area and summarized to estimate the risk for all Japan. To estimate annual risk, both of 70 and 75 years of age were used as a mean life span. When the unit risk and mean life span of 75 years was used, annual lung cancer death was estimated to be 5, 277 (1, 143-21, 109), which correspond to 11.5 (2.5-46.2)% of annual lung cancer death in Japan in 1995. The calculated risk value may be a future risk for the present exposure level when long latent periods in carcinogenesis are considered.
