绵阳市室内空气氡浓度调查

Investigation on indoor air radon concentration in Mianyang City

目的:调查绵阳市室内空气氡浓度并分析其影响因素。方法:2020年至2021年在绵阳市各区(市)县城选择居住、办公等场所布点,进行90d的累积空气氡浓度测量,并测量室内、外γ剂量率水平。回收后的氡采集盒交由国家疾控中心辐射安全所统一计算,获得氡浓度数据,单个房间仅有一个采样点时,室内氡浓度为单个氡采集盒测得数据,同一室内测量点大于1个时,取多个测量点读数的平均值。采用单样本t检验和秩和检验分别分析室内外γ辐射水平差异和不同因素对室内空气氡浓度的影响。结果:在绵阳市辖区内126场所放置184个氡采集盒,获得126个场所的室内空气氡浓度数据,氡浓度水平范围37.88~251.00Bq/m^(3),均值为64.34±21.53Bq/m^(3),室内外γ辐射水平差异显著(t=2.847,P=0.006),建筑材料主要为空心砖的房屋室内空气氡浓度要高于以黏土砖为材料的建筑(H=6.932,P=0.031)。结论:绵阳市室内空气氡浓度均未超出国家标准限值(300Bq/m^(3)),但高于邻近地区,并会增加γ射线剂量率;室内通风情况差、使用放射性水平高的建筑材料会增加室内空气氡浓度。

Objective:To investigate indoor radon concentrations in Mianyang City and analyze its influencing factors.Methods:From 2020 to 2021,sampling points were set up in residential and office buildings in urban and rural areas of each district(city)in Mianyang City to measure the cumulative radon concentration over 90 days,and indoor and outdoorγdose rate levels.The collected radon detectors were sent to the Radiation Safety Institute of the Chinese CDC for unified calculation to obtain radon concentration data.If there was only one sampling point in a single room,the indoor radon concentration was the data measured by the single radon detector;if there were more than one measurement point in the same indoor,the average of readings from multiple measurement points was taken.Single sample t-test and rank sum test were used to analyze the differences in indoor and outdoorγradiation levels and the influence of different factors on indoor radon concentrations,respectively.Results:184 radon collection boxes were placed in 126 sites within the jurisdiction of Mianyang City,and indoor radon concentration data of 126 sites were obtained,with radon concentration levels ranging from 37.88 to 251.00 Bq/m^(3) and a mean of 64.34±21.53 Bq/m^(3).The indoor and outdoorγradiation levels differed significantly(t=2.847,P=0.006).The radon concentration in buildings made of hollow bricks as the main material was higher than that in buildings made of clay bricks(H=6.932,P=0.031).Conclusion:The indoor radon concentrations in Mianyang City were all below the national standard limit(300 Bq/m^(3)),but higher than neighboring areas,which could increaseγdose rates.Poor indoor ventilation and use of building materials with higher radioactivity could increase indoor radon concentrations.