@article{oai:repo.qst.go.jp:00080536,
 author = {Hosoda, Masahiro and Djatnika Nugraha, Eka and Akata, Naofumi and Yamada, Ryohei and Tamakuma, Yuki and Sasaki, Michiya and Kelleher, Kevin and Yoshinaga, Shinji and Suzuki, Takahito and Pornnumpa  Rattanapongs, Chanis and Masahide Furukawa and Yamaguchi, Masaru and Kazuki Iwaoka and Sanada, Tetsuya and Miura, Tomisato and Kusdiana and Iskandar, Dadong and Pudjadi, Eko and Kashiwakura, Ikuo and Tokonami, Shinji and Iwaoka, Kazuki},
 journal = {Science of the Total Environment},
 month = {Jan},
 note = {The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h-1 and 1109 nGy h-1. Indoor radon concentrations ranged from 124 Bq m-3 to 1015 Bq m-3. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bqm-3 recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.},
 title = {A unique high natural background radiation area – Dose assessment and Perspectives},
 volume = {750},
 year = {2021}
}