Assessment of Regional Mercury Deposition and Emission Outflow in Mainland China. Issue 17 (12th September 2018)

• Record Type: Journal Article
• Authors: Wang, Xun; Lin, Che‐Jen; Feng, Xinbin; Yuan, Wei; Fu, Xuewu; Zhang, Hui; Wu, Qingru; Wang, Shuxiao
• Is Part Of: Journal of geophysical research. Volume 123:Issue 17(2018)
• Page Start: 9868
• Page End: 9890
• Publication Date: 2018-09-12
• Subjects: mercury pollution -- mass balance -- CMAQ‐Hg -- deposition -- emission outflow; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2018JD028350
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Mainland China is the largest emission region of anthropogenic mercury (Hg) in the world. There have been concerns regarding the emission outflow and chemical transport budget of Hg in the region. Earlier assessments of Hg chemical transport were based on relatively outdated emission data. Recent estimates for anthropogenic (Wu et al., 2016, https://doi.org/10.1021/acs.est.6b04308 ) and natural Hg emissions (X. Wang, Lin, et al., 2016, https://doi.org/10.5194/acp‐16‐11125‐2016 ) show substantial differences from earlier emission inventories. In this study, we applied the updated Hg emission estimates to reassess the regional transport budget using Community Multiscale Air Quality‐Hg v5.1. Our results show that the variation of simulated concentration, deposition, and associated emission outflow of Hg are primarily influenced by the spatial‐temporal variation of Hg emissions, monsoon shifts, and particulate matter pollution in China. Total Hg deposition in Mainland China is estimated to be 422 Mg/year, and approximately two thirds of the deposition is contributed by domestic emissions. The net Hg transport budget from Mainland China is 511 Mg/year, contributing to 10% of Hg deposition in other regions of the world. This reassessment points to a ~25% reduction in total annual outflow compared to the previous estimate by Lin et al. (2010, https://doi.org/10.5194/acp‐10‐1853‐2010 ). Such reduction is mainly caused by changes in Hg emission quantity, speciation, and spatial/temporal distributions. More modeling studies focusing on reducing uncertainties of emission inventories and Hg atmospheric chemistry are needed for continuous assessment of Hg emission outflow in this emission‐intensive region. Key Points: Recent changes in emission inventories have significant influences on atmospheric mercury outflow from China Total mercury deposition in China is 422 Mg/year, about two thirds of deposition is contributed by domestic emissions Elevated levels of aerosol and secondary air pollutants significantly enhance atmospheric mercury pollution