Abstract
In Japan, the increasing automobile traffic has caused considerable increases in the levels of nitrogen dioxide and suspended particulate matter primarily derived from automobile exhausts in urban areas. In the districts adjacent to trunk roads, the potential effect of these concentrations on the health of residents is a matter of concern. Our epidemiological study in Chiba Prefecture showed that the prevalence and the incidence of asthma were significantly higher among school children who lived in the roadside areas than among school children in the other areas, even after adjustment for potential confounding factors such as the history of allergic diseases. A large-scale cohort study by the Japanese Ministry of the Environment (the SORA project) has also shown the significant relationship between the incidence of asthma in school children and elemental carbon levels, which have been estimated to evaluate exposure to traffic-related air pollution. Regarding the health effects of fine particulate matter (PM2.5), a short-term exposure to considerably low concentrations of PM2.5 was associated with a decrease in the pulmonary function and occurrence of wheezing among asthmatic children. In order to clarify the health effects of air pollution including PM2.5, interdisciplinary approaches should be further conducted.
