摘要:Various indoor air pollution caused by reduced air change rate in recent Japanese houses, which comes from highly insulated building envelops as an energy conservation measure, is getting very serious social problems in this country. Some of them is called “sick house syndrome”, which is an indoor air quality (IAQ) problems caused by chemicals emitted from building materials, and is drawing an enthusiastic public attentions. However so far as a lung cancer, indoor radon is much higher risk than those chemicals. Literature review was made in order to clarify present status of the pollution and to overlook the indoor radon pollution research in this country. The results show that the most important point of understanding the radon progeny behaviors and of developing the mitigation measure is air exchange including ventilation. It is strongly expected that consensus on the radon risk and lung dose should be reached among the researchers of health physics and environmental standards should be set based on the consensus. It is also expected the instruments which can exactly measure by the inexperienced persons in order to establish the radon inspection systems.