北京地区大气中^（212）Pb浓度的测定及所致居民剂量

MEASUREMENTS OF ￣(212)Pb CONCENTRATION IN THEGROUND-LEVEL AIR IN BEIJING AREA ANK ASSESSMENT OF IONIZING RADIATION EXPOSURE OF THE POPULATION

本文介绍了用ＮａＩ（Ｔｌ）－塑料反符合低本底γ谱仪测定大气中￣（２１２）Ｐｂ浓度的方法以及于１９８８．２－１９８９．１对北京地区３２９ｄ空气中￣（２１２）Ｐｂ浓度的测定结果。结果表明，大气中￣（２１２）Ｐｂ浓度呈对数正态分布，算术均值和单次测量标准差分别为０．５４和０．４０Ｂｑ·ｍ￣（－３）；几何均值和几何标准差分别为０．４４Ｂｑ·ｍ￣（－３）和２．０。每年７、８月份雨季￣（２１２）Ｐｂ浓度最低（０．４２Ｂｑ·ｍ￣（－３））；冬季取暖季节最高（０．６６Ｂｑ·ｍ￣（－３））；￣（２１２）Ｐｂ浓度的昼夜变化亦很大，凌晨００－０４时最高，午后１２－１８时最低，最高／最低为４．８。根据实际测量值估算了北京地区居民吸入所子体所致公众年有效剂量为２１０μＳｖ，室内１６０μＳｖ，室外为５０μＳｖ。

This paper discribes the method of measuring ￣(212)Pb concentration in the ground-level air with a gamma spectrometer and the results of the measurements of ￣(212)Pb concentra-tions during February 1988-January 1989. The results showed that the average and stan-dard deviation are 0. 54 and 0. 40Bq·m￣(-3); the distrabution of ￣(212)Pb concentrations in air waslogarithmic normal distrabution, geometric average and geometric standard deviation are0. 44Bq·m￣(-3) and 2.0. The ￣(212)Pb concentration in rain season is the lowest(0. 42Bq·m￣(-3))while in heating season is the highest(0. 66 Bq·m￣(-3)). In period of a day,￣(212)Pb concentra-tion in the morning 0-4 o'clock is the highest and in the afternoon 12-18 o'clock is the low-est,￣(212)Pb(max)/￣(212)Pb(min)=4.8.