東京都および隣接県における屋内・外ラドン濃度の測定および統計解析 [in Japanese] Measurements and Statistical Analyses of Indoor Radon Concentrations in Tokyo and Surrounding Areas [in Japanese]
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Since the UNSCEAR Report published in 1982, radiation exposure to the respiratory tract due to radon and its progeny has been regarded as the single largest contributor to the natural radiation exposure of the general public. In Japan, the measurement of radon gas concentrations in many types of buildings have been surveyed by national and private institutes. We also carried out the measurement of radon gas concentrations in different types of residential buildings in Tokyo and its adjoining prefectures from October, 1988 to September 1991, to evaluate the potential radiation risk of the people living there. One or two simplified passive radon monitors were set up in each of the 34 residential buildings located in the above-mentioned area for an exposure pepiod of 3 months each. Comparing the average concentrations in the buildings of different materials and structures, those in the concrete steel buildings were always higher than those in the wooden and the prefabricated mortared buildings. The radon concentrations were proved to become higher in autumn and winter, and lower in spring and summer. Radon concentrations in an underground room of a concrete steel building showed the highest value throughout our investigation, and statistically significant seasonal variation was detected by the X-11 Method developed by the U. S. Bureau of Census. The values measured in a room at the first floor of the same concrete steel building also showed seasonal variation, but the phase of variation was different.<br>Another multivariate analysis suggested that the building material and structure are the most important factors concerning the levels of radon concentration among other factors such as the age of the building and the use of ventilators.
- Jpn. J. Health Phys.
Jpn. J. Health Phys. 30(4), 293-301, 1995-12-01
Japan Health Physics Society