我国大气环境中汞污染现状

综述了最近几十年中国大气汞的排放、分布、传输和沉降方面的研究.中国人为源每年汞排放量为世界最高,达到500~700t左右,超过全球人为排放量的25%~30%,并以每年4.2%的速度增加.通过已有观测和模型估算,中国来自自然地表过程(包括裸露地、地表水和森林土壤等)的汞排放量与人为源汞排放量相当,不容忽视.中国城市、农村和偏远地区大气汞浓度分布和变化范围很大,城市地区的总气态汞(TGM)浓度是北美和欧洲地区相似城市类型TGM的1.5~5倍左右;中国城市颗粒态汞(PHg)浓度比北美和欧洲地区高出2个数量级;中国沿海地区和偏远的背景区TGM、PHg和活性汞(RGM)低于中国内地城市地区,但是也明显高于背景值和北美和欧洲地区.相应地,高含量的大气汞浓度导致大量的大气汞沉降到地表,城市地区和背景区大气汞沉降分别比北美地区高出1~2个数量级和1~2倍.

Chinese atmospheric mercury pollution status

China's economy has developed rapidly in recent decades, but it also brought the persistent pollutants of mercury emissions to the atmosphere rapidly. Mercury as a global pollutant, Chinese mercury emission has received a considerable attention internationally. Thus, this paper reviews the current understanding of and knowledge on atmospheric Hg emissions, distribution transport and deposition in China. Anthropogenic mercury annual emissions from China was the highest in the word and up to about 500~700t, which was more than 25~30% of the global anthropogenic emissions and with an annual increase rate of 4.6%. Emissions of Hg from natural surfaces (including bare soil, water, and vegetation covered soil) was comparable to anthropogenic emissions by the estimation from existing model. Atmospheric Hg exhibits a significant concentration variability among urban, semi-remote, and remote areas. Total Gaseous Mercury (TGM) concentrations in urban areas of China were often 1.5~5 folds higher compared to the corresponding settings in North America and Europe. In turn, particulate mercury (PHg) concentrations in urban areas of China were up to two orders of magnitude higher compared to North America and Europe. TGM, PHg and reactive gaseous mercury (RGM) in coastal areas and remote areas of China were lower than that in central cities, but they were still higher than the corresponding settings in North America and Europe. Accordingly, Hg deposition fluxes tended to be higher in China, with urban areas and remote areas being 1~2 magnitude and1~2 times higher than those in North America and Europe, respectively.