[Estimation of Health Risk Posed by Road Traffic Noise in Japan Based on the Environmental Noise Guidelines for the European Region].

Objectives: Traffic noise exposure is associated with adverse health effects such as environmental sleep disorder, ischaemic heart disease (IHD), stroke and diabetes. The health risks posed by traffic noise were estimated to be quite high in European countries. However, in Japan, no estimation has ever been conducted. In the present study, we estimated the health risk posed by road traffic noise in Japan.

Methods: We estimated the risks of environmental sleep disorder (high sleep disturbance) and IHD caused by road traffic noise in Japan as of 2015 on the basis of existing noise-exposure estimates, vital statistics of deaths, and patient survey with exposure-response relationships proposed by the Environmental Noise Guidelines for the European Region issued in 2018. We employed old information on noise exposure in 1994 because it is the only information currently available in Japan. We also estimated the health risks of noise exposure levels that were equivalent to the Japanese environmental quality standards.

Results: The estimated numbers of patients with environmental sleep disorder and IHD caused by road traffic noise were approximately 1,200,000 and 9,000, respectively. The estimated number of mortalities from IHD was approximately 1,700. The noise exposure level equivalent to the Japanese noise standards caused a lifetime mortality rate of more than 10^-2, which was extremely high as an environmental health risk.

Conclusions: As in European countries, road traffic noise was one of the most important environmental risk factors in Japan. However, the current Japanese noise standards are insufficient for the protection of public health.