Investigation on radon exposure level in 38 districts and counties in Chongqing

Abstract

Objective In order to understand the radon exposure level of homes in Chongqing, this survey was carried out on the indoor radon concentration in 38 districts and counties of Chongqing.

Methods According to the population ratio of every 100 000 people, one monitoring site was arranged, and the number of parallel samples was 10% of the distribution sites. The monitoring sites covered 38 districts and counties in Chongqing. A total of 1 019 residential monitoring sites in 38 districts and counties in Chongqing were measured with radon accumulation detectors from July 2020 to June 2021.

Results The five districts/counties in Chongqing having the highest average concentration of residential radon in the year were Xiushan County 78.8 Bq/m ³, Qianjiang District 78.0 Bq/m ³, Yubei District 73.9 Bq/m ³, Youyang County 71.4 Bq/m ³ and Shapingba District 69.8 Bq/m ³. The five districts/counties with the lowest mean concentration of indoor radon were 37.6 Bq/m ³ in Zhongxian County, 36.4 Bq/m ³ in Changshou District, 33.7 Bq/m ³ in Kaizhou District, 33.2 Bq/m ³ in Liangping District and 27.3 Bq/m ³ in Wushan County. The concentration levels of radon in four seasons were 46.0 Bq/m ³, 53.4 Bq/m ³, 45.1 Bq/m ³ and 59.5 Bq/m ³, respectively. The concentration of radon was higher in Summer and Winter, and lower in Spring and Autumn, and the difference of concentration among four seasons was statistically significant ( P<0.001). The radon concentration of newly built buildings after 2017 was relatively high, up to 61.8 Bq/m ³, but there was no statistical significance in radon concentration in different building ages ( P>0.05). The concentration of radon in rooms of buildings with less than 10 floors was higher, up to 63.2 Bq/m ³, and there were significant differences in radon concentration among rooms of different floors ( P<0.05). The average annual radon concentration in houses in Chongqing was about (51.6±19.5) Bq/m ³, and the average annual effective dose of inhaling radon and its progeny by house-related people was about (1.38±0.52) mSv.

Conclusion The average annual radon concentration level of houses in Chongqing is within the standard limit value recommended by China, but the prevention and control of radon should be strengthened.

Abstract

摘要： 目的 了解重庆市居室氡暴露水平, 为重庆市居室氡防控提供依据。 方法 2020年7月一2021年6月, 按 照人口比例每10万人口, 布置1个监测点, 平行样数量为分配布点数的10%, 监测点覆盖重庆市38个区县。采用氡累 积探测器对重庆市38个区县共1 019个居室监测点进行氡浓度测量。 结果 重庆市各区县年度居室氡均值浓度较髙 的秀山县、黔江区、渝北区、酉阳县和沙坪坝区分别为78.8、78.0、73.9、71.4和69.8 Bq/m ³; 居室氡浓度均值较低的忠县 长寿区、开州区、梁平区、和巫山县分别为37.6、36.4、33.7、33.2和27.3 Bq/m ³; 重庆市4个季节居室氡浓度水平分别为 46.0、53.4、45.1和59.5 Bq/m ³, 呈现夏季和冬季居室氡浓度较髙, 春季和秋季居室氡浓度较低的特点, 且4个季度居室氡 浓度差异有统计学意义( P<0.001); 2017 年以后新建的建筑居室氡浓度偏髙, 最髙可达到61.8 Bq/m ³, 但不同建筑年代 房屋居室氡浓度差异无统计学意义( P>0.05); 10 层以下的建筑居室氡浓度偏髙, 最髙可达到63.2 Bq/m ³, 且不同楼层房 屋居室氡浓度存在显著差异( P<0.05)。重庆市居室年均氡浓度约(51.6±19.5) Bq/m ³, 居室相关人员吸人氡及其子体产 生的年均有效剂量为(1.38±0.52) mSv。 结论 重庆市居室年均氡浓度水平在我国推荐的标准限值内, 但居室氡对人 体健康的不良影响仍需重视, 应尽可能的加强防氡控氡措施。