Oxidation of mercury by bromine in the subtropical Pacific free troposphere

Autor: Lyatt Jaeglé, Nicola J. Blake, Shaojie Song, Frank Flocke, Lynne E. Gratz, J. L. Ambrose, Xianliang Zhou, Viral Shah, Rebecca S. Hornbrook, Geoffrey S. Tyndall, D. J. Knapp, Catalina Tsai, Andrew J. Weinheimer, Samuel R. Hall, Meghan Stell, Denise D. Montzka, Eric C. Apel, Daniel M. Stechman, Mike Reeves, Noelle E. Selin, Daniel A. Jaffe, Max Spolaor, James Festa, Jochen Stutz, Teresa Campos
Rok vydání: 2015
Předmět:
Zdroj: Geophysical Research Letters. 42
ISSN: 1944-8007
0094-8276
Popis: Mercury is a global toxin that can be introduced to ecosystems through atmospheric deposition. Mercury oxidation is thought to occur in the free troposphere by bromine radicals, but direct observational evidence for this process is currently unavailable. During the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks campaign, we measured enhanced oxidized mercury and bromine monoxide in a free tropospheric air mass over Texas. We use trace gas measurements, air mass back trajectories, and a chemical box model to confirm the origin and chemical history of the sampled air mass. We find the presence of elevated oxidized mercury to be consistent with oxidation of elemental mercury by bromine atoms in this subsiding upper tropospheric air mass within the subtropical Pacific High, where dry atmospheric conditions are conducive to oxidized mercury accumulation. Our results support the role of bromine as the dominant oxidant of mercury in the upper troposphere.
Databáze: OpenAIRE
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