Somchai BovornkittiPornsri PolpongMahidol UniversityThailand Ministry of Science and Technology2018-07-042018-07-041996-10-01Chest. Vol.110, No.4 SUPPL. (1996)001236922-s2.0-33750225988https://repository.li.mahidol.ac.th/handle/20.500.14594/17709The potential hazards posed by exposure to radiation from indoor radon gas audits daughter products has been of great concern worldwide. The U.S. Department of Health and Human Services has proclaimed that radon may be second only to smoking as a cause of lung cancer. Although awareness of such environmental issues and their relationship to health is growing in most developed countries, enthusiasm is not widespread in developing countries such as Thailand. Only in 1994 was a pilot survey begun; it was followed by general surveys in different areas of the country. This communication, which describeds the results of surveys in eight provinces, reveals that radon concentration range from 1 to 1,974 Bq.m-3. The U.S. Environmental Protection Agency (EPA) has established the safety threshold level at 4 pCi/liter (148 Bq.m-3). The highlight of the survey was the finding that the indoor radon levels on some upper floors of four multi-storey concrete buildings studied were significantly higher than those obtained on the ground-contact or lower floors. It concludes that indoor radon is ubiquitous in nature and its source is not only from the natural ground-soils but also from other sources inside buildings, most likely emission from construction materials containing radium.Mahidol UniversityMedicineArticleSCOPUS