title: Mercury Emission Ratios from Coal-Fired Power Plants in the Southeastern United States during NOMADSS.
abstract: We use measurements made onboard the National Science Foundation's C-130 research aircraft during the 2013 Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) experiment to examine total Hg (THg) emission ratios (EmRs) for six coal-fired power plants (CFPPs) in the southeastern U.S. We compare observed enhancement ratios (ERs) with EmRs calculated using Hg emissions data from two inventories: the National Emissions Inventory (NEI) and the Toxics Release Inventory (TRI). For four CFPPs, our measured ERs are strongly correlated with EmRs based on the 2011 NEI (r(2) = 0.97), although the inventory data exhibit a -39% low bias. Our measurements agree best (to within ±32%) with the NEI Hg data when the latter were derived from on-site emissions measurements. Conversely, the NEI underestimates by approximately 1 order of magnitude the ERs we measured for one previously untested CFPP. Measured ERs are uncorrelated with values based on the 2013 TRI, which also tends to be biased low. Our results suggest that the Hg inventories can be improved by targeting CFPPs for which the NEI- and TRI-based EmRs have significant disagreements. We recommend that future versions of the Hg inventories should provide greater traceability and uncertainty estimates.
authors.affiliation: School of Science, Technology, Engineering, and Mathematics, Physical Sciences Division, University of Washington , Bothell, Washington 98011, United States.
authors.forename: Jesse L
authors.initials: JL
authors.lastname: Ambrose
authors.affiliation: School of Science, Technology, Engineering, and Mathematics, Physical Sciences Division, University of Washington , Bothell, Washington 98011, United States.
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Gratz
authors.affiliation: School of Science, Technology, Engineering, and Mathematics, Physical Sciences Division, University of Washington , Bothell, Washington 98011, United States.|Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Jaffe
authors.affiliation: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado 80307, United States.
authors.forename: Teresa
authors.initials: T
authors.lastname: Campos
authors.affiliation: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado 80307, United States.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Flocke
authors.affiliation: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado 80307, United States.
authors.forename: David J
authors.initials: DJ
authors.lastname: Knapp
authors.affiliation: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado 80307, United States.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Stechman
authors.affiliation: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado 80307, United States.
authors.forename: Meghan
authors.initials: M
authors.lastname: Stell
authors.affiliation: Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado 80307, United States.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Weinheimer
authors.affiliation: Department of Atmospheric and Oceanic Sciences, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Cantrell
authors.affiliation: Department of Atmospheric and Oceanic Sciences, University of Colorado , Boulder, Colorado 80309, United States.|Department of Physics, University of Helsinki , Helsinki FI-00014, Finland.
authors.forename: Roy L
authors.initials: RL
authors.lastname: Mauldin
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis; D001272:Atmosphere / Q000737:chemistry; D002245:Carbon Dioxide / Q000032:analysis; D003031:Coal / Q000032:analysis*; D016014:Linear Models; D008628:Mercury / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D016877:Oxidants / Q000737:chemistry*; D011210:Power Plants; D015144:Southeastern United States; D013458:Sulfur Dioxide / Q000032:analysis
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D003031:Coal; D016877:Oxidants; D013458:Sulfur Dioxide; D002245:Carbon Dioxide; D008628:Mercury; D009584:Nitrogen