汞在不同粒径大气颗粒物中的分布

PARTICLE SIZE DISTRIBUTIONS OF ATMOSPHERIC MERCURY IN BEIJNG

采用DFG 1型五段分级采样装置及冷蒸汽原子荧光法 ,对北京市冬、春、夏和秋季不同粒径大气颗粒物 (分别为≤ 1 1μm ,1 1— 2 0 μm ,2 0— 3 3μm ,3 3— 7 0 μm和≥ 7 0 μm )中的汞进行分析 .结果表明 :北京大气颗粒物中汞的浓度在 0 6 0— 3 95ng·m-3 之间 ,冬季平均浓度为 2 85ng·m-3 ,远大于其它季节 ;大气颗粒物中的汞呈双峰分布 ,在≤ 1 1μm的细颗粒和粗粒径处各有一峰值 ;北京大气颗粒物中的汞主要分布在≤ 1 1μm的细颗粒中 ,不同粒径颗粒物中汞的分布随季节变化而变化 ,冬季各粒径颗粒物中汞的浓度比其它季节高 ;大气颗粒物中汞的质量中值粒径 (MMD )冬季为 0 71μm ,其它季节均大于1 0 μm ;北京大气颗粒物中的汞至少有 5 0 %可进入人体呼吸系统 。

Mercury on different diameter airborne particles (≤ 1.1μm,1.1—2.0μm,2.0—3.3μm,3.3—7.0μm和≥7.0μm) were determined with cold vapor atomic fluorescence in different seasons in Beijing.The results were showed that the concentration of particulate Hg was 0.60—3.95 ng·m -3, and mean concentration was 2.85 ng·m -3 in winter, which much higher than the other seasons.The distribution of particulate Hg was bimodal with an obvious fine and coarse mode.The main part of atmospheric particulate mercury was distributed fine particles(≤ 1.1μm), and the percent of mercury in different diameter to that in total particulate matter was change with seasons, and in winter the concentration of mercury in different sizes was highest of all seasons.The value of mass media diameter (MMD) of particulate mercury in winter was 0.71μm, and that was more than 1.0 μm in other seasons.There was no less than 50% of particulate mercury can inhale into human body, especially in winter.