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Overview Mercury Deposition Network (MDN) in NC. Jim Bowyer, PhD NC Division of Air Quality Toxics Protection Branch Raleigh, NC. Mercury In the Atmosphere. Three types (species) Elemental Mercury vapor (Hg 0 ) - >98% of the mercury species in the air
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Overview Mercury Deposition Network (MDN) in NC Jim Bowyer, PhD NC Division of Air Quality Toxics Protection Branch Raleigh, NC
Mercury In the Atmosphere Three types (species) Elemental Mercury vapor (Hg0) - >98% of the mercury species in the air - longest transport range, globally Reactive Gaseous Mercury (RGM) - divalent mercury (HgCl2) - short range transport Particulate Bound Mercury (PBM) - short range transport
Mercury Deposition Dry deposition Atmospheric transfer to surfaces during dry weather & occurs at all times to all surfaces. Deposits all three types of atmospheric Hg. Wet deposition – Atmospheric transfer to surfaces thru precipitation (rain, snow, etc) Deposits all three but more readily water soluble RGM & PBM.
Mercury Deposition Network Mercury wet-deposition monitoring arm of the National Atmospheric Deposition Program (NADP) Begun in 1996 Provides a nationally consistent survey of mercury wet-deposition concentration & fluxes showing regional & international deposition patterns. Identifies long-term pattern changes in wet-deposition rates over time and space. Provides high-quality data for use in estimating wet deposition rates locally or between sites, and for current and future mercury policy and modeling efforts.
MDN Sites Pettigrew Candor Elkmont (Great Smokies) Waccamaw
Field Operations • Wet deposition sampling (rain water) • Weekly composite samples • Collected every Tuesday • Analyses at Frontier Geosciences, Bothell, WA • Data analysis by University of Illinois, Champaign
MDN Total Hg Deposition Seasonal From MDN Brochure http://nadp.sws.uiuc.edu/lib/brochures/mdn.pdf
Links to Additional Information Mercury Deposition Network Web Page http://nadp.sws.uiuc.edu/MDN/ http://nadp.sws.uiuc.edu/lib/brochures/mdn.pdf NC Division Air Quality Mercury Information http://daq.state.nc.us/quick/mercury/ National Atmospheric Deposition Program (NADP) Annual Reports http://nadp.sws.uiuc.edu/lib/dataReports.aspx
Questions Contact Information Jim Bowyer NC DAQ, Chemist III 919-715-7484 Jim.Bowyer@ncdenr.gov