Mercury speciation in a coal‐fired power plant plume: An aircraft‐based study of emissions from the 3640 MW Nanticoke Generating Station, Ontario, Canada

Deeds, Daniel A.; Banic, C. M.; Lu, Junjie; Daggupaty, S. M.

doi:10.1002/jgrd.50349

Cited by 32 publications

(33 citation statements)

References 51 publications

(87 reference statements)

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“…Despite large uncertainties in all these estimates, we conclude that GOM emissions represent less than 25 % of the total mercury emissions. This result is consistent with 20 % found by Schütze et al (2015) in stack gases of the Lippendorf CFPP in 2013 and findings by others Stergašek et al, 2008;Wang et al, 2010;Deeds et al, 2013). It suggests that GOM fractions of ∼ 40 % of CFPP mercury emissions in current emission inventories are overestimated.…”

Section: Discussionsupporting

confidence: 90%

“…Thus, part of the difference between GOM in stack gases of the Lippendorf CFPP and the Crist CFPP can result from day-to-day variations in GOM removal efficiency. Putting this unresolved issue aside, low fractions of GOM emissions reported here and by others Stergašek et al, 2008;Wang et al, 2010;Deeds et al, 2013) are in contrast to the AMAP/UNEP geospatially distributed mercury emissions data set "2010v1" (Wilson et al, 2013), which splits the speciated mercury emissions from combustion in power plants to 50 GEM, 40 GOM, and 10 % PBM. As mentioned before, the FGD in the Lippendorf CFPP is made by washing the flue gas with CaO suspension with added sulfidic precipitant.…”

Section: Gom Emissionscontrasting

confidence: 62%

“…Wang et al (2010) found GOM fractions of 6-25 % of all Hg emissions from five Chinese power plants with FGD. Deeds et al (2013) found 13 % of total mercury being GOM in the plume of the Nanticoke CFPP in Canada. They think that discrepancy between this and the 43 % GOM fraction found in stack gases is due to sampling biases.…”

Section: Gom Emissionsmentioning

confidence: 98%

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Mercury emissions of a coal-fired power plant in Germany

et al. 2016

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Abstract. Hg / SO 2 , Hg / CO, NO x / SO 2 (NO x being the sum of NO and NO 2 ) emission ratios (ERs) in the plume of the coal-fired power plant (CFPP), Lippendorf, near Leipzig, Germany, were determined within the European Tropospheric Mercury Experiment (ETMEP) aircraft campaign in August 2013. The gaseous oxidized mercury (GOM) fraction of mercury emissions was also assessed. Measured Hg / SO 2 and Hg / CO ERs were within the measurement uncertainties consistent with the ratios calculated from annual emissions in 2013 reported by the CFPP operator, while the NO x / SO 2 ER was somewhat lower. The GOM fraction of total mercury emissions, estimated using three independent methods, was below ∼ 25 %. This result is consistent with other findings and suggests that GOM fractions of ∼ 40 % of CFPP mercury emissions in current emission inventories are overestimated.

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Section: Discussionsupporting

confidence: 90%

Section: Gom Emissionscontrasting

confidence: 62%

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Mercury emissions of a coal-fired power plant in Germany

et al. 2016

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“…For ASGM, we use the Emissions Database for Global Atmospheric Research gridded inventory (9). II is partitioned thermodynamically between the gas and particle phase on the basis of local temperatures and total aerosol concentration computed with a GEOS-Chem aerosol simulation (43 (45,46). Redox chemistry also takes place in the surface ocean and soil reservoirs, which receive atmospheric deposition and reemit to atmosphere through land-air and sea-air exchanges.…”

Section: Methodsmentioning

confidence: 99%

Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions

Zhang

Jacob

Horowitz

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

312

258

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). These decreases are inconsistent with current global emission inventories indicating flat or increasing emissions over that period. However, the inventories have three major flaws: (i) they do not account for the decline in atmospheric release of Hg from commercial products; (ii) they are biased in their estimate of artisanal and small-scale gold mining emissions; and (iii) they do not properly account for the change in Hg 0 /Hg II speciation of emissions from coal-fired utilities after implementation of emission controls targeted at SO 2 and NO x . We construct an improved global emission inventory for the period 1990 to 2010 accounting for the above factors and find a 20% decrease in total Hg emissions and a 30% decrease in anthropogenic Hg 0 emissions, with much larger decreases in North America and Europe offsetting the effect of increasing emissions in Asia. Implementation of our inventory in a global 3D atmospheric Hg simulation [GEOS-Chem (Goddard Earth Observing System-Chemistry)] coupled to land and ocean reservoirs reproduces the observed large-scale trends in atmospheric Hg 0 concentrations and in Hg II wet deposition. The large trends observed in North America and Europe reflect the phase-out of Hg from commercial products as well as the cobenefit from SO 2 and NO x emission controls on coal-fired utilities.mercury | trend | emission | atmosphere

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“…Atmospheric reduction mechanisms for Hg II are poorly understood, but photoreduction in aquatic systems has been widely observed (Costa and Liss, 1999;Amyot et al, 2000;Mason et al, 2001). Fast in-plume reduction of Hg II emitted by coal-fired power plants was first reported by and Lohman et al (2006), but more recent field observations suggest that on average only 5 % (range 0-55 %) of emitted Hg II is reduced in the plume (Deeds et al, 2013;Landis et al, 2014). Recent aircraft observations and emission inventories suggest that previous reports of in-plume reduction of Hg II may reflect in part an overestimate of Hg II emissions.…”

Section: Introductionmentioning

confidence: 99%

A new mechanism for atmospheric mercury redox chemistry: implications for the global mercury budget

et al. 2017

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Abstract. Mercury (Hg) is emitted to the atmosphere mainly as volatile elemental Hg 0 . Oxidation to water-soluble Hg II plays a major role in Hg deposition to ecosystems. Here, we implement a new mechanism for atmospheric Hg 0 / Hg II redox chemistry in the GEOS-Chem global model and examine the implications for the global atmospheric Hg budget and deposition patterns. Our simulation includes a new coupling of GEOS-Chem to an ocean general circulation model (MITgcm), enabling a global 3-D representation of atmosphereocean Hg 0 / Hg II cycling. We find that atomic bromine (Br) of marine organobromine origin is the main atmospheric Hg 0 oxidant and that second-stage HgBr oxidation is mainly by the NO 2 and HO 2 radicals. The resulting chemical lifetime of tropospheric Hg 0 against oxidation is 2.7 months, shorter than in previous models. Fast Hg II atmospheric reduction must occur in order to match the ∼ 6-month lifetime of Hg against deposition implied by the observed atmospheric variability of total gaseous mercury (TGM ≡ Hg 0 + Hg II (g)). We implement this reduction in GEOS-Chem as photolysis of aqueous-phase Hg II -organic complexes in aerosols and clouds, resulting in a TGM lifetime of 5.2 months against deposition and matching both mean observed TGM and its variability. Model sensitivity analysis shows that the interhemispheric gradient of TGM, previously used to infer a longer Hg lifetime against deposition, is misleading because Southern Hemisphere Hg mainly originates from oceanic emissions rather than transport from the Northern Hemisphere.The model reproduces the observed seasonal TGM variation at northern midlatitudes (maximum in February, minimum in September) driven by chemistry and oceanic evasion, but it does not reproduce the lack of seasonality observed at southern hemispheric marine sites. Aircraft observations in the lowermost stratosphere show a strong TGM-ozone relationship indicative of fast Hg 0 oxidation, but we show that this relationship provides only a weak test of Hg chemistry because it is also influenced by mixing. The model reproduces observed Hg wet deposition fluxes over North America, Europe, and China with little bias (0-30 %). It reproduces qualitatively the observed maximum in US deposition around the Gulf of Mexico, reflecting a combination of deep convection and availability of NO 2 and HO 2 radicals for second-stage HgBr oxidation. However, the magnitude of this maximum is underestimated. The relatively low observed Hg wet deposition over rural China is attributed to fast Hg II reduction in the presence of high organic aerosol concentrations. We find that 80 % of Hg II deposition is to the global oceans, reflecting the marine origin of Br and low concentrations of organic aerosols for Hg II reduction. Most of that deposition takes place to the tropical oceans due to the availability of HO 2 and NO 2 for second-stage HgBr oxidation.

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Mercury speciation in a coal‐fired power plant plume: An aircraft‐based study of emissions from the 3640 MW Nanticoke Generating Station, Ontario, Canada

Cited by 32 publications

References 51 publications

Mercury emissions of a coal-fired power plant in Germany

Mercury emissions of a coal-fired power plant in Germany

Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions

A new mechanism for atmospheric mercury redox chemistry: implications for the global mercury budget

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