HR: 1340h
AN: A43C-0079    [Abstracts]
TI: Modeling the Atmospheric Formation of Reactive Mercury in Florida and the Great Lakes
AU: * Sillman, S
EM: sillman@umich.edu
AF: University of Michigan, Department of Atmospheric, Oceanic and Space Sciences, Ann Arbor, MI 48109-2143 United States
AU: Marsik, F J
EM: marsik@umich.edu
AF: University of Michigan, Department of Atmospheric, Oceanic and Space Sciences, Ann Arbor, MI 48109-2143 United States
AU: Al-Wali, K I
EM: kalwali@umich.edu
AF: University of Michigan, Department of Atmospheric, Oceanic and Space Sciences, Ann Arbor, MI 48109-2143 United States
AU: Landis, M S
AF: US EPA, National Exposure Research Laboratory, Research Triangle Pa, NC 27711 United States
AU: Keeler, G J
EM: jkeeler@umich.edu
AF: University of Michigan, Department of Atmospheric, Oceanic and Space Sciences, Ann Arbor, MI 48109-2143 United States
AB: Reactive mercury in the troposphere is affected by a complex mix of local emissions, global-scale transport, and gas and aqueous-phase chemistry. Here, we describe a modified version of the EPA model for urban/regional air quality (CMAQ) to include the chemistry of mercury, and model applications focusing on the Great Lakes region and on South Florida. The University of Michigan modifications to CMAQ include an integrated numerical solver for gas-phase and aqueous photochemistry, improved representation of in-cloud photolysis rates, and up-to-date reaction schemes for mercury chemistry. Reactive mercury is produced primarily by gas-phase reactions. Aqueous reactions tend to convert reactive mercury back to its elemental form, but the most important aqueous reactions (with HO2 and O2-) are problematic (Gartfeld and Jonnson, 2003). Model results suggest that gas-phase conversion from elemental to reactive mercury can lead to high concentrations of reactive mercury in the middle troposphere. Reactive mercury in the lower troposphere is removed more rapidly through both wet and dry deposition and potentially through aqueous conversion to elemental mercury. Model results are compared with a suite of comprehensive gas and aerosol measurements performed in Michigan and during aircraft measurements in S. Florida. Model results suggest that direct emission of reactive mercury contribute to atmospheric deposition in source regions. This work has been funded wholly or in part by the United States Environmental Protection Agency Office of Research and Development. ˙It has been subjected to peer review and approved for publication.
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting