1998 Fiscal Year Final Research Report Summary
Measurement of ambient benzene and human health assessment
| Project/Area Number |
08458150
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | Yokohama National University |
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Principal Investigator |
NAKANISHI Junko Yokohama National University, Institute of Environmental Science and Technology, Professor, 環境科学研究センター, 教授 (10010836)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Noriyuki Kanazawa Institute of Technology, Faculty of Engineering, Assistant Professor, 工学部, 助教授 (40196853)
HANAI Yoshimichi Yokohama National University, Institute of Environmental Science and Technology,, 環境科学研究センター, 助手 (00114984)
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| Project Period (FY) |
1996 – 1998
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| Keywords | benzene / cancer risk / Nitrogen Oxide / cost / air pollution / exposure |
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| Research Abstract |
The population cancer risk due to ambient benzene was evaluated for the entire Japanese population. For predicting ambient benzene levels, nitrogen oxide (NOx) levels measured at a large number of monitoring stations set throughout Japan were used. The relationships between ambient benzene and Nox levels were investigated by continuous monitoring experiment at the Yokohama National University from May, 1997 to November, 1998. As a result of monitoring, the regression equation, Y = 0.18 X 0.81, was obtained between NOx levels (X in ppb) and benzene levels (Y in mu g/m^3) with a high correlation coefficient (R^2 = 0.73). This result indicates that ambient NOx monitoring data can be used for reliable prediction of ambient benzene level
In Japan, NOx levels in the ambient environment have been precisely monitored and their hourly average values have been recorded at 1461 general air pollution monitoring stations nationwide and at 382 automobile exhaust monitoring stations adjacent to major roads. Exposure analysis was performed considering the population represented by each monitoring station.
The population weighted average benzene levels were estimated to be 3.2 mu g/m^3 for the entire population, and 47 percent of the entire population was estimated to be exposed to benzene at a level above the Environmental Quality Standard level of 3 mu g/m^3. The distribution of excess cancer risk due to exposure to ambient benzene was established based on the EPA cancer unit risk. Our results indicated that about 79 percent of the entire population was exposed to a lifetime cancer risk level of 1 x 10^<-5> or greater, and the excess lifetime cancer risk due to one-year-exposure to benzene was estimated to be about 30 cases. The cost per one life saved per year by countermeasure that reduces benzene content in gasoline was estimated to be bout 3 billion yen.
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