长三角背景地区秋冬季节大气气态总汞含量特征研究

利用Tekran 2537B大气汞分析仪于2009年9月15日～2009年12月17日对上海崇明岛大气气态总汞(TGM)进行了连续监测.监测期间,崇明地区气态总汞的平均含量为2.50 ng·m-3±1.50 ng·m-3,高于北半球背景浓度1.5～1.7 ng·m-3,月均浓度9月<10月<11月<12月.9～12月,崇明地区气态总汞含量的日变化规律为上午08:00～10:00出现峰值,白天气态总汞浓度水平与夜间基本一致.崇明地区气态总汞含量和一氧化碳含量具有较好的相关性,表明崇明地区大气汞主要来自火电厂和工业锅炉的燃煤排放.从风向和后向轨迹模型分析的结果来看,崇明岛的大气汞主要来自西部的大陆地区,尤其是位于崇明西北部的江苏、山东等地.9月和10月盛行来自海面的东风,因而气态总汞含量较低,11月和12月盛行来自大陆工业区的西北风,导致崇明气态总汞含量较高.

Characteristics of Total Gaseous Mercury Concentrations at a Rural Site of Yangtze Delta, China

The ambient concentrations of total gaseous mercury (TGM) in Chongming Island, Shanghai, were continuously observed using the Tekran 2537B mercury analyzer from 15th September to 17th December, 2009. The average concentration of TGM during our observation is (2.50±1.50) ng·m^-3, much higher than the background TGM of north hemisphere. The TGM concentration increased from September to December. During September to December, the concentration peaks appear during 08:00-10:00 am and the daytime TGM concentration approximately equaled that in the night. The TGM in Chongming significantly correlated with concentrations of CO, which indicates that TGM most likely comes from the coal combustion of power plants and industrial boilers. The back trajectory analysis demonstrates the atmospheric mercury in Chongming Island mainly comes from inland China, especially Jiangsu province and Shandong province which locate in the northwest of Chongming. The mercury concentrations are lower in September and October since the airflow is mainly from the eastern ocean. In November and December, the atmospheric mercury content is much higher because the northwest wind brings the pollutants from the western industrial areas.