title: The Estimated Six-Year Mercury Dry Deposition Across North America.
abstract: Dry deposition of atmospheric mercury (Hg) to various land covers surrounding 24 sites in North America was estimated for the years 2009 to 2014. Depending on location, multiyear mean annual Hg dry deposition was estimated to range from 5.1 to 23.8 μg m-2yr-1to forested canopies, 2.6 to 20.8 μg m-2yr-1to nonforest vegetated canopies, 2.4 to 11.2 μg m-2yr-1to urban and built up land covers, and 1.0 to 3.2 μg m-2yr-1to water surfaces. In the rural or remote environment in North America, annual Hg dry deposition to vegetated surfaces is dominated by leaf uptake of gaseous elemental mercury (GEM), contrary to what was commonly assumed in earlier studies which frequently omitted GEM dry deposition as an important process. Dry deposition exceeded wet deposition by a large margin in all of the seasons except in the summer at the majority of the sites. GEM dry deposition over vegetated surfaces will not decrease at the same pace, and sometimes may even increase with decreasing anthropogenic emissions, suggesting that Hg emission reductions should be a long-term policy sustained by global cooperation.
authors.affiliation: Environment and Climate Change Canada, Toronto, Ontario, Canada.
authors.forename: Leiming
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Environment and Climate Change Canada, Toronto, Ontario, Canada.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Environment and Climate Change Canada, Toronto, Ontario, Canada.
authors.forename: Irene
authors.initials: I
authors.lastname: Cheng
authors.affiliation: Independent Researcher, Stratford, Prince Edward Island, Canada.
authors.forename: L Paige
authors.initials: LP
authors.lastname: Wright
authors.affiliation: National Atmospheric Deposition Program, University of Illinois , Champaign, Illinois 61801, United States.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Olson
authors.affiliation: National Atmospheric Deposition Program, University of Illinois , Champaign, Illinois 61801, United States.
authors.forename: David A
authors.initials: DA
authors.lastname: Gay
authors.affiliation: U.S. Geological Survey, Indianapolis, Indiana 46278, United States.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Risch
authors.affiliation: The University of Tennessee Space Institute , Tullahoma, Tennessee 37388, United States.
authors.forename: Steven
authors.initials: S
authors.lastname: Brooks
authors.affiliation: University of Maryland , Frostburg, Maryland 21532, United States.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Castro
authors.affiliation: GreenReach LLC, Glouster, Ohio 45732, United States.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Conley
authors.affiliation: Atmospheric Research & Analysis, Inc., Cary, North Carolina 27513, United States.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Edgerton
authors.affiliation: Clarkson University , Potsdam, New York 13699, United States.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Holsen
authors.affiliation: NOAA Air Resources Laboratory, College Park, Maryland 20740, United States.
authors.forename: Winston
authors.initials: W
authors.lastname: Luke
authors.affiliation: Environment and Climate Change Canada, Dartmouth, Nova Scotia, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Tordon
authors.affiliation: University of California , Santa Cruz, California 95064, United States.
authors.forename: Peter
authors.initials: P
authors.lastname: Weiss-Penzias
mesh_terms: D000393:Air Pollutants; D004784:Environmental Monitoring; D065928:Forests; D008628:Mercury; D012621:Seasons
chemical_list: D000393:Air Pollutants; D008628:Mercury