Department of Radiological Technology, Faculty of Health Sciences, Hokkaido University of Science, Sapporo, Hokkaido 006-8585, Japan.
Int J Environ Res Public Health. 2021 Feb 1;18(3):1299. doi: 10.3390/ijerph18031299.
As part of a nationwide survey of thoron (Rn) in Japan, the indoor Rn gas concentrations in 940 dwellings were measured throughout one year, from 1993 to 1996, using a passive type Rn-Rn discriminative monitor. The monitor was placed in a bedroom or a living room in each house for four successive three-month periods. The mean annual indoor Rn concentration was estimated from the four measurements in each house. The arithmetic mean, the median and the geometric mean for indoor Rn concentrations in 899 dwellings were 20.1, 9.6 and 10.0 Bq m, respectively. The Rn concentrations exhibited a log-normal distribution. It was found that the Rn concentrations were dependent on the nature of the materials used for wall construction and also on the distance of measurement from the wall. Significant seasonal variations in the Rn concentration were not observed. It would seem that the nature of the wall material contributed to the increased indoor Rn concentrations.
作为日本全国范围内氡（Rn）调查的一部分，从 1993 年到 1996 年，使用被动式 Rn-Rn 甄别监测仪，对 940 处住所的室内 Rn 气体浓度进行了为期一年的测量。监测仪在每个房屋的卧室或客厅中放置了四个连续的三个月。根据每个房屋的四次测量结果，估算出了年度室内 Rn 浓度。899 处住所的室内 Rn 浓度的算术平均值、中位数和几何平均值分别为 20.1、9.6 和 10.0 Bq m。Rn 浓度呈对数正态分布。结果发现，Rn 浓度取决于墙壁建筑材料的性质，也取决于距墙壁的测量距离。未观察到 Rn 浓度的明显季节性变化。似乎墙壁材料的性质导致了室内 Rn 浓度的增加。
