title: Measurement of radon/thoron exhalation rates and gamma-ray dose rate in granite areas in Japan.
abstract: Radon and thoron exhalation rates and gamma-ray dose rate in different places in Hiroshima Prefecture were measured. Exhalation rates were measured using an accumulation chamber method. The radon exhalation rate was found to vary from 3 to 37 mBq m(-2) s(-1), while the thoron exhalation rate ranged from 40 to 3330 mBq m(-2) s(-1). The highest radon exhalation rate (37 mBq m(-2) s(-1)) and gamma-ray dose rate (92 nGy h(-1)) were found in the same city (Kure City). In Kure City, indoor radon and thoron concentrations were previously measured at nine selected houses using a radon-thoron discriminative detector (Raduet). The indoor radon concentrations varied from 16 to 78 Bq m(-3), which was higher than the average value in Japan (15.5 Bq m(-3)). The indoor thoron concentration ranged from ND (not detected: below a detection limit of approximately 10 Bq m(-3)) to 314 Bq m(-3). The results suggest that radon exhalation rate from the ground is an influential factor for indoor radon concentration.
authors.affiliation: National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555,  Japan.
authors.forename: G
authors.initials: G
authors.lastname: Prasad
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: M
authors.initials: M
authors.lastname: Hosoda
authors.forename: S K
authors.initials: SK
authors.lastname: Sahoo
authors.forename: N
authors.initials: N
authors.lastname: Kavasi
authors.forename: A
authors.initials: A
authors.lastname: Sorimachi
authors.forename: S
authors.initials: S
authors.lastname: Tokonami
authors.forename: S
authors.initials: S
authors.lastname: Uchida
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods; D005720:Gamma Rays; D005843:Geography; D006798:Housing; D007564:Japan; D011834:Radiation Monitoring / Q000379:methods*; D011874:Radiometry / Q000379:methods; D011886:Radon / Q000032:analysis*; D012588:Scintillation Counting / Q000379:methods; D012822:Silicon Dioxide; D013997:Time Factors
chemical_list: D000396:Air Pollutants, Radioactive; C007886:granite; D012822:Silicon Dioxide; D011886:Radon