Emission of Hg from Coal Consumption in China and Its Summertime Deposition Calculated by CMAQ-Hg

Mercury (Hg) emission from coal combustion in China is estimated in this study and its deposition calculated using the Models-3 Community Multi-scale Air Quality (CMAQ-Hg) modeling system with meteorological fields calculated by MM5. Three kinds of Hg speciation were included in the models: particle-bound mercury (PHg), gaseous elemental mercury (GEM) and gas oxidized mercury (RGM). Much of the Hg was released as RGM from coal combustion in China, accounting for 58.4 - 66.8% of total emissions. The large proportion of RGM in overall Hg emission also led to large Hg deposition. Based on simulations, Hg deposition originating from coal combustion reaches as high as 2 - 6 mu g m(-2) month(-1) in southwestern China (particularly Guizhou Province), the industrialized and populated regions of east central and coastal China, and Liaoning Province in the northeast.