"ESTIMATION OF AMBIENT CONCENTRATIONS OF 1,3-BUTADIENE IN JAPAN" 

Kazuaki Mita, Haruyuki Higashino, Hiroshi Yoshikado

National Institute of Advanced Industrial Science and Technology

8th International Conference for Atmospheric Sciences and Applications to Air Quality (Tsukuba, Japan 2003/3/11)

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Abstract

The available epidemiological and toxicological data suggest that 1,3-butadiene is carcinogenic in humans and may also be genotoxic in humans. Therefore, human risks of 1,3-butadiene must be assessed. The general population is exposed to 1,3-butadiene primarily through ambient and indoor air. On the other hand, contribution of exposure routes other than the atmosphere, such as food and drinking water, is negligibly small (in the case of 1,3-butadiene). Therefore, it is important to estimate concentration of 1,3-butadiene in the ambient atmosphere for performing the risk assessment.

Emission sources of 1,3-butadiene estimated in this study are gasoline- and diesel-powered vehicles, off-road vehicles and machinery, airplanes and ships, and industrial on-site uses. The total Japanese 1,3-butadiene emission to the atmosphere in 1999 has been estimated at 3.7 kt/y (gasoline- and diesel-powered vehicles: 2.3 kt/y, off-road vehicles and machinery: 0.5 kt/y, industrial sources: 0.8 kt/y, others: 0.1 kt/y). The total Japanese emission has been decreasing during past years. This is primarily caused by the reduction in emissions from industrial sources.

Regional scale ambient concentrations of 1,3-butadiene were estimated for 5 x 5 km square grid spatial resolution with AIST-ADMER model in the Kanto area of Japan. Annual mean concentrations are estimated 0.1 - 0.4μg/m3. At most sites, these levels are driven by emissions from motor vehicles and concentrations are generally higher in urban areas. Emissions of 1,3-butadiene from industrial sources elevate 1,3-butadiene concentrations to 0.5 - 1 μg/m3.

Ambient concentrations of 1,3-butadiene around two major industrial sites were estimated with METI-LIS model (0.2 x 0.2 km square grid spatial resolution). Annual mean concentrations are estimated 2 - 3μg/m3 near industrial source and 0.5 - 1μg/m3 at the residential area, respectively.

Keywords

1,3 butadiene, risk, exposure, ADEMR, METI-LIS