skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Measurement of Indoor Radon-222 and Radon-220 Concentrations in Central Japan

Abstract

A passive-type radon/thoron detector was used for measuring indoor radon and thoron concentrations at 90 dwellings in Aichi and Gifu prefectures in central Japan during 90 days from December, 2006 to March, 2007. The radon and thoron concentrations were 21.1 Bq/m3 and 25.1 Bq/m3, respectively. The dose due to radon and thoron in dwellings was roughly evaluated as 0.7 mSv/y and 2.4 mSv/y, respectively. The examination of the geological factor and house condition having an effect on indoor radon concentration was performed.

Authors:
;  [1]; ; ; ;  [2]
  1. Graduate School of Health Science, Fujita Health University 1-98, Dengakugakubo, Kutsukake, Tyoake, Aichi, 470-1192 (Japan)
  2. National Institute of Radiological Sciences 4-9-1, Anagawa, Inage, Chiba 263-8555 (Japan)
Publication Date:
OSTI Identifier:
21152437
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1034; Journal Issue: 1; Conference: NRE-VIII: 8. International symposium on the natural radiation environment, Buzios, RJ (Brazil), 7-12 Oct 2007; Other Information: DOI: 10.1063/1.2991205; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ALPHA DETECTION; DIELECTRIC TRACK DETECTORS; ECOLOGY; GEOLOGY; HOUSES; JAPAN; RADIATION DOSES; RADIATION MONITORING; RADON; RADON 220; RADON 222

Citation Formats

Oka, Mitsuaki, Shimo, Michikuni, Tokonami, Shinji, Sorimachi, Atsuyuki, Takahashi, Hiromichi, and Ishikawa, Tetsuo. Measurement of Indoor Radon-222 and Radon-220 Concentrations in Central Japan. United States: N. p., 2008. Web. doi:10.1063/1.2991205.
Oka, Mitsuaki, Shimo, Michikuni, Tokonami, Shinji, Sorimachi, Atsuyuki, Takahashi, Hiromichi, & Ishikawa, Tetsuo. Measurement of Indoor Radon-222 and Radon-220 Concentrations in Central Japan. United States. doi:10.1063/1.2991205.
Oka, Mitsuaki, Shimo, Michikuni, Tokonami, Shinji, Sorimachi, Atsuyuki, Takahashi, Hiromichi, and Ishikawa, Tetsuo. 2008. "Measurement of Indoor Radon-222 and Radon-220 Concentrations in Central Japan". United States. doi:10.1063/1.2991205.
@article{osti_21152437,
title = {Measurement of Indoor Radon-222 and Radon-220 Concentrations in Central Japan},
author = {Oka, Mitsuaki and Shimo, Michikuni and Tokonami, Shinji and Sorimachi, Atsuyuki and Takahashi, Hiromichi and Ishikawa, Tetsuo},
abstractNote = {A passive-type radon/thoron detector was used for measuring indoor radon and thoron concentrations at 90 dwellings in Aichi and Gifu prefectures in central Japan during 90 days from December, 2006 to March, 2007. The radon and thoron concentrations were 21.1 Bq/m3 and 25.1 Bq/m3, respectively. The dose due to radon and thoron in dwellings was roughly evaluated as 0.7 mSv/y and 2.4 mSv/y, respectively. The examination of the geological factor and house condition having an effect on indoor radon concentration was performed.},
doi = {10.1063/1.2991205},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1034,
place = {United States},
year = 2008,
month = 8
}
  • In an area of unusually high indoor radon concentrations of up to 270,000 Bq m{sup {minus}3}, four houses were selected for mitigation of indoor radon. Methods used were basement sealing, soil depressurization, a mechanical intake and outlet ventilation system with heat exchanger in the basement, and a multilayer floor construction using a fan to such radon from a layer between bottom slab and floor. Basement sealing proved unsuccessful, the radon concentration remained unchanged after the mitigation attempt. The most successful remedial measure was soil depressurization using two fans and loops of drainage tubes to withdraw radon from the region undermore » the floor and outside the walls of the basement and from soil under the part of the house without a basement. This method reduced the basement radon level in winter by about a factor of 200, i.e., from 100,000 Bq m{sup {minus}3} to 500 Bq m{sup {minus}3}, and the ground-floor level by about a factor of 400. As regards the mechanical intake and outlet ventilation system with heat exchanger in the basement, it is essential to ensure that ventilation provides increased air pressure in the basement compared to outdoors. Unbalanced mechanical intake and outlet ventilation may decrease the air pressure indoors compared to outdoors, leading to increased radon concentrations. Optimization of this method reduced radon concentrations for 200,000 Bq m{sup {minus}3} to 2,000-3,000 Bq m{sup {minus}3} in winter. In one house with only a very small basement, a multilayer floor construction using a fan to such radon from a layer between the bottom slab and floor was found to reduce radon concentrations on the ground floor from 25,000 Bq m{sup {minus}3} to about 1,700 Bq m{sup {minus}3} in winter. The results show that even in areas with extremely high radon concentrations, effective mitigation of indoor radon can be accomplished if suitable techniques are used. 8 ref., 7 figs., 6 tabs.« less
  • In a village in western Tyrol, Austria (Umhausen, 2,600 inhabitants), unusually high indoor radon concentrations were measured, and the lung cancer mortality rate was found to be higher than that of the total population of Tyrol (620,000 inhabitants). Annual means of radon concentrations were found to be particularly high in the area between the two rivers Oetztaler Ache and Hairlachbach, geologically in alluvial fan of a giant rock slide of granitic gneisses (area A, median of annual means on the ground floors: 1,868 Bq m{sup {minus}3}); radon concentrations were comparatively low in the rest of the village (area B, medianmore » of annual means on the ground floors: 182 Bq m{sup {minus}3}). On the basis of these medians, the annual exposures were calculated according to the ICRP model (area A: 58.8 x 10{sup 5} Bq h m{sup {minus}3}; area B: 5.7 x 10{sup 5} Bq h m{sup {minus}3}). Data taken from the Cancer Registry of Tyrol were used to determine the age- and sex-standardized lung cancer mortality rate (area A: 6.17; area B: 1.43). 7 refs., 3 figs., 3 tabs.« less
  • Measurements in a full-scale experimental facility are used to benchmark a semiempirical model for predicting indoor radon concentrations for Florida-style houses built using slab-on-grade construction. The model is developed to provide time-averaged indoor radon concentrations from quantitative relationships between the time-dependent radon entry and elimination mechanisms that have been demonstrated to be important for this style of residential construction. The model successfully predicts indoor radon concentrations in the research structure for several pressure and ventilation conditions. Parametric studies using the model illustrate how different ventilation strategies affect indoor radon concentrations. It is demonstrated that increasing house ventilation rates by increasingmore » the effective leakage area of the house shell does not reduce indoor radon concentrations as effectively as increasing house ventilation rates by controlled duct ventilation associated with the heating, ventilating, and air conditioning system. The latter strategy provides the potential to minimize indoor radon concentrations while providing positive control over the quality of infiltration air. 9 refs., 5 figs.« less
  • Since indoor radon exposures take place over many years while radon measurement periods are shorter, we are studying the yearly variation of indoor radon concentrations in approximately 100 houses located throughout Minnesota. Most houses were initially measured for one or more years in the late 1980`s and for 5 consecutive years starting in 1990. Two houses have been monitored for 12 y. Each year, two alpha track detectors were placed on the two lowest livable levels. The year-to-year variations averaged about 35% (corrected for instrumental uncertainties) in both basements and first floors. The minimum observed variation was 5% and themore » maximum was 130%. Some homes have shown substantial variation associated with Structural modifications. While most homes show no obvious systematic trends, a few houses have shown temporal trends that may be associated with aging or climate. We are studying possible correlation between year-to-year radon variation, climatic variables (yearly-average and seasonal such as heating/cooling degree days, precipitation, soil moisture), and structural changes.« less
  • Measured surface radium content, geologic province information, information on the fraction of homes with basements and with living-area basements, and measurements from the EPA/State Residential Radon Surveys, were used in a Bayesian mixed effects regression to predict the distributions of short-term winter and annual living-area average radon concentrations by county in the mid-Atlantic states. The information provided by those explanatory variables is roughly equivalent to collecting an extra 12 observations per county, effectively doubling the amount of information in a typical county. Predicted county geometric means are subject to standard errors of 15 % to 30 % for typical counties,more » with the Uncertainty in a given county depending on the number of radon measurements in the county and the amount of information about the geologic province that contains the county. After controlling for soil radium concentration and the effect of measuring in a basement vs. the first floor, typical geologic provinces are found to be associated with elevation or depression of indoor radon concentrations by 30% on average, with some provinces having effects of considerably larger magnitude. 20 refs., 7 figs., 3 tabs.« less