衡阳市大气颗粒物中^(210)Po的活度-粒径分布测量

Measurements of ^(210)Po Activity-Particle Size Distribution in Hengyang Atmospheric Particles

利用大流量撞击式分级采样器、放化分离提纯技术和α谱仪测量技术,建立了针对大气颗粒物中210Po的活度及活度-粒径分布的测量方法,并应用该方法分别于春季和秋季对衡阳市城区大气颗粒物中210Po的活度及活度-粒径分布进行了测量。实验测量结果表明,衡阳市城区大气颗粒物中210Po的含量处于正常水平;总体积比活度和质量比活度的分布范围分别为:0.012 5 m Bq·m-3~1.165 8m Bq·m-3、0.459 7 Bq·g-1~13.859 8 Bq·g-1,体积比活度含量占TSP中总含量93%的210Po存在于粒径范围小于3.0μm(PM3.0)的颗粒物中;雾霾天气会提高公众所接受的天然内照射剂量;同时发现雨水对大气颗粒物中210Po的净化作用较为明显。

Using high volume cascade impactor , radiochemical purification technique and alpha -spectrometer measurement technology ,the method was built for measuring 210 Po activity and the activity -particle size distri-bution in atmospheric particulate .210 Po activity and activity -particle size distribution in the atmospheric partic-ulate of Hengyang city was be measured by this method during the spring and autumn .Results of the measure-ment show that ,the level of 210 Po is normal in the atmospheric particulate of Hengyang city ,as volume specific activity and weight specific activity are 0.0125 mBq· m^-3 -1.1658 mBq· m^-3 ,0.459 7 Bq· g^-1 -13.859 8 Bq· g ^-1 .volume specific activity 93 percent of 210 Po is be contained in the TSP atmospheric particulate which particle-size is less 3.0μm （PM3.0）;It will improve public acceptance within the natural exposure dose in the haze weather;And 210 Po of atmospheric particulate is been purification more obvious in the rain .