Acceptable Risk Level for the Japanese Public Regarding Atmospheric Carcinogens

Abstract

In Japan, the lifetime cancer risk level of 10^-5 is used to set the ambient air quality standard for benzene, which is a well-established cause of cancer in humans. This study assessed the “acceptable” risk level for the Japanese public aged 20–59 years regarding atmospheric carcinogen(s). Results of face-to-face questionnaire surveys conducted in 2014 indicated that more than half the respondents selected annual cancer risk level of “one in one million” or over as “acceptable”. Five percent of respondents demanded “zero-risk”, and twenty percent did not answer their “acceptable risk level” for atmospheric carcinogen(s). Moreover, the results of investigations conducted from 1999 through 2014 suggest that the acceptable risk levels for carcinogenic substances in the air have tended to increase over time.