Evaluation of Human Health Risks From Exposures to Four Air Pollutants in the Indoor and the Outdoor Environments in Tokushima, and Communication of the Outcomes to the Local People

The Law concerning Reporting etc., of Releases to the Environment of Specific Chemical Substances, and Promoting Improvement in Their Management (the so-called Pollutant Release and Transfer Register Law or the PRTR Law) was promulgated in Japan in 1999. Estimated amounts of the specific chemical substances released from their major emission sources to local environments are publicly available by law. Concentrations of benzene, toluene, xylene (i.e., volatile organic compounds or VOCs) and formaldehyde specified by law were measured in different seasons from 2003 to 2005 both at outdoor and indoor sites within the Tokushima University campus and in a nearby local area to estimate their human exposures. There were no substantial differences between the indoor and the outdoor concentrations of benzene, toluene, and xylene. Higher concentrations observed for formaldehyde in the indoor environment than in the outdoor environment in the 2003 winter season could be explained by the fact that there was renovation of the building nine months before the measurement. The exposure data obtained were used to evaluate the possible human health risks of these four chemicals by referring to their health criteria. The results indicated that the overall risks from the exposures to these chemicals both in the indoor and the outdoor environments were not significantly high even if fluctuations are taken into account. The results of our evaluation were released on the university website and also presented and discussed at a public meeting and three PRTR data seminars in the local society.