Abstract
The World Health Organization (WHO) Regional Office for Europe has established indoor air quality (IAQ) guidelines for benzene and naphthalene. However, these chemicals are not subjected to the guideline values for indoor air concentrations in Japan (Japanese IAQ guideline). Therefore, this survey was investigated the pollution level of benzene and naphthalene in houses. We measured the indoor and outdoor air at 28 houses in Japan four times a year and assessed their seasonal variations. The results showed that benzene had high indoor air concentrations from December to March. Also, indoor benzene concentrations in many houses exceeded the WHO IAQ guideline values. The naphthalene concentration in one house exceeded the WHO IAQ guideline values throughout the year although overall concentrations of other houses measured were low. Further, the indoor concentrations of benzene and naphthalene were higher than the outdoor concentrations in most houses, indicating that these pollution sources were originated from indoors. The results obtained from this survey will be useful for the considering to set of Japanese IAQ guideline for benzene and naphthalene in the future.
