Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 7103-7125, 2015
https://doi.org/10.5194/acp-15-7103-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
30 Jun 2015
Top-down constraints on atmospheric mercury emissions and implications for global biogeochemical cycling
S. Song1, N. E. Selin1,2, A. L. Soerensen3,4, H. Angot5, R. Artz6, S. Brooks7, E.-G. Brunke8, G. Conley9, A. Dommergue5, R. Ebinghaus10, T. M. Holsen11, D. A. Jaffe12,13, S. Kang14,15, P. Kelley6,16, W. T. Luke6, O. Magand5, K. Marumoto17, K. A. Pfaffhuber18, X. Ren6,16, G.-R. Sheu19, F. Slemr20, T. Warneke21, A. Weigelt10, P. Weiss-Penzias22, D. C. Wip23, and Q. Zhang24 1Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
2Engineering Systems Division, Massachusetts Institute of Technology, Cambridge, MA, USA
3Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA
4Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden
5Univ. Grenoble Alpes, CNRS, LGGE, Grenoble, France
6Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD, USA
7Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee Space Institute, Tullahoma, TN, USA
8South African Weather Service c/o CSIR, Stellenbosch, South Africa
9Center for Air Quality, Ohio University, Athens, OH, USA
10Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
11Department of Civil and Environmental Engineering, Clarkson University, Potsdam, NY, USA
12School of Science, Technology, Engineering and Mathematics, University of Washington, Bothell, WA, USA
13Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
14State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences (CAS), Lanzhou, China
15CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, China
16Cooperative Institute for Climate and Satellites, University of Maryland, College Park, MD, USA
17Environmental Chemistry Section, National Institute for Minamata Disease, Kumamoto, Japan
18Norwegian Institute for Air Research (NILU), Tromsø, Norway
19Department of Atmospheric Sciences, National Central University, Jhongli, Taiwan
20Max Planck Institute for Chemistry, Air Chemistry Division, Mainz, Germany
21Institute of Environmental Physics, University of Bremen, Bremen, Germany
22Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA
23Anton de Kom Universiteit van Suriname, Paramaribo, Suriname
24Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
Abstract. We perform global-scale inverse modeling to constrain present-day atmospheric mercury emissions and relevant physiochemical parameters in the GEOS-Chem chemical transport model. We use Bayesian inversion methods combining simulations with GEOS-Chem and ground-based Hg0 observations from regional monitoring networks and individual sites in recent years. Using optimized emissions/parameters, GEOS-Chem better reproduces these ground-based observations and also matches regional over-water Hg0 and wet deposition measurements. The optimized global mercury emission to the atmosphere is ~ 5.8 Gg yr−1. The ocean accounts for 3.2 Gg yr−1 (55 % of the total), and the terrestrial ecosystem is neither a net source nor a net sink of Hg0. The optimized Asian anthropogenic emission of Hg0 (gas elemental mercury) is 650–1770 Mg yr−1, higher than its bottom-up estimates (550–800 Mg yr−1). The ocean parameter inversions suggest that dark oxidation of aqueous elemental mercury is faster, and less mercury is removed from the mixed layer through particle sinking, when compared with current simulations. Parameter changes affect the simulated global ocean mercury budget, particularly mass exchange between the mixed layer and subsurface waters. Based on our inversion results, we re-evaluate the long-term global biogeochemical cycle of mercury, and show that legacy mercury becomes more likely to reside in the terrestrial ecosystem than in the ocean. We estimate that primary anthropogenic mercury contributes up to 23 % of present-day atmospheric deposition.

Citation: Song, S., Selin, N. E., Soerensen, A. L., Angot, H., Artz, R., Brooks, S., Brunke, E.-G., Conley, G., Dommergue, A., Ebinghaus, R., Holsen, T. M., Jaffe, D. A., Kang, S., Kelley, P., Luke, W. T., Magand, O., Marumoto, K., Pfaffhuber, K. A., Ren, X., Sheu, G.-R., Slemr, F., Warneke, T., Weigelt, A., Weiss-Penzias, P., Wip, D. C., and Zhang, Q.: Top-down constraints on atmospheric mercury emissions and implications for global biogeochemical cycling, Atmos. Chem. Phys., 15, 7103-7125, https://doi.org/10.5194/acp-15-7103-2015, 2015.
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Short summary
A better knowledge of mercury (Hg) emission fluxes into the global atmosphere is important for assessing its human health impacts and evaluating the effectiveness of corresponding policy actions. We for the first time apply a top-down approach at a global scale to quantitatively estimate present-day mercury emission sources as well as key parameters in a chemical transport model, in order to better constrain the global biogeochemical cycle of mercury.
A better knowledge of mercury (Hg) emission fluxes into the global atmosphere is important for...
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