Dry deposition of gaseous oxidized mercury in Western Maryland

Castro, Mark S.; Moore, C. W.; Sherwell, John; Brooks, Steve

doi:10.1016/j.scitotenv.2011.12.044

Cited by 45 publications

(66 citation statements)

References 18 publications

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“…In previous studies, scaling factors similar to HNO 3 (α = β = 10) were used to calculate oxidized Hg dry-deposition velocity Castro et al, 2012); however, Lyman et al (2007) used the effective Henry's Law constant, and half-redox reactions in neutral solutions of HgCl 2 , and indicated HONO might better represent the chemical properties of oxidized Hg rather than HNO 3 . Huang and Gustin (2015a) indicated that due to limited understanding of oxidized Hg chemical properties, no single value can be used to calculate oxidized Hg dry deposition, because α and β would change with different GOM compounds.…”

Section: Data Analysesmentioning

confidence: 99%

“…Some researchers considered that GOM is similar to HNO 3 (α = β = 10), and some treated GOM as HONO (α = β = 2) (Castro et al, 2012;Lyman et al, 2007;Marsik et al, 2007); however, using the parameters of HNO 3 could overestimate GOM dry-deposition velocities due to the differences of effective Henry's law constants (HgCl 2 : ∼ 10 6 HNO 3 : ∼ 10 13 M atm −1 ). If the ratios (HgBr 2 : 1.6, HgCl 2 : 2.4, HgSO 4 : 2.3, HgO : 3.7, and HgN 2 O 6 q H 2 O : 12.6) of GOM concentrations measured by the Tekran ® vs. cation-exchange membranes for different GOM-permeated compounds Huang et al, 2013) are used to correct Tekran ® GOM data in this study, modeled GOM dry deposition (Fig.…”

Section: Start Datementioning

confidence: 99%

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Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA

et al. 2017

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Section: Data Analysesmentioning

confidence: 99%

Section: Start Datementioning

confidence: 99%

Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA

et al. 2017

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“…Gas-phase reactions for Hg Castro et al (2012) report total deposition of all mercury species; Castro et al (2012) report only gaseous oxidized mercury, which is expected to be the majority of total mercury deposition. Average, minimum, and maximum annual deposition estimates from CMAQ-Hg are compared with equivalent or scaled values from model and measurement estimates (Caldwell et al, 2006;Castro et al, 2012;EPA, 1997;Landis et al, 2004;Lyman et al, 2007; …”

Section: Chemical Equation Ratementioning

confidence: 99%

“…Average, minimum, and maximum annual deposition estimates from CMAQ-Hg are compared with equivalent or scaled values from model and measurement estimates (Caldwell et al, 2006;Castro et al, 2012;EPA, 1997;Landis et al, 2004;Lyman et al, 2007; …”

Section: Chemical Equation Ratementioning

confidence: 99%

An assessment of atmospheric mercury in the Community Multiscale Air Quality (CMAQ) model at an urban site and a rural site in the Great Lakes Region of North America

et al. 2012

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Abstract. Quantitative analysis of three atmospheric mercury species -gaseous elemental mercury (Hg 0 ), reactive gaseous mercury (RGHg) and particulate mercury (PHg) -has been limited to date by lack of ambient measurement data as well as by uncertainties in numerical models and emission inventories. This study employs the Community Multiscale Air Quality Model version 4.6 with mercury chemistry (CMAQ-Hg), to examine how local emissions, meteorology, atmospheric chemistry, and deposition affect mercury concentration and deposition the Great Lakes Region (GLR), and two sites in Wisconsin in particular: the rural Devil's Lake site and the urban Milwaukee site. Ambient mercury exhibits significant biases at both sites. Hg 0 is too low in CMAQ-Hg, with the model showing a 6 % low bias at the rural site and 36 % low bias at the urban site. Reactive mercury (RHg = RGHg + PHg) is over-predicted by the model, with annual average biases > 250 %. Performance metrics for RHg are much worse than for mercury wet deposition, ozone (O 3 ), nitrogen dioxide (NO 2 ), or sulfur dioxide (SO 2 ). Sensitivity simulations to isolate background inflow from regional emissions suggests that oxidation of imported Hg 0 dominates model estimates of RHg at the rural study site (91 % of base case value), and contributes 55 % to the RHg at the urban site (local emissions contribute 45 %).

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“…In addition, we conducted additional field and laboratory tests to better understand the potential for loss of GOM when deployed over 1 month, and tested a new cation-exchange membrane material for collection of GOM, because the cation-exchange material previously used has been phased out by the manufacturer. 19,26,31 High GOM concentrations (up to 300 pg m −3 ) have been observed at high elevation sites in the Western US and in the free troposphere using KCl-coated denuders, the Tekran system, the Detector for Oxidized Hg Species (DOHGS), and passive systems. 19,32−37 Most high GOM events were correlated with dry air, high ozone concentrations, and air masses that originated above the planetary boundary.…”

Section: ■ Introductionmentioning

confidence: 99%

Use of Passive Sampling Methods and Models to Understand Sources of Mercury Deposition to High Elevation Sites in the Western United States

Huang

Gustin

2014

Environ. Sci. Technol.

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To understand gaseous oxidized mercury (GOM) sources to the Western US, data were collected with passive samplers for ambient GOM concentrations and dry deposition at 10 sites from the coast of the Pacific Ocean to Great Basin National Park. Tests were done to better understand the samplers and the materials used. Measured dry deposition of GOM was significantly higher at sites >2000 m elevation relative to those below due to high GOM concentrations and atmospheric turbulence. At these high elevation sites, GOM dry deposition was higher in spring due to long-range transport from Asia (air parcels from the free troposphere) and some high GOM dry deposition events were related to regional emissions. Dry deposition of GOM at two sites was calculated using the passive sampler data and a multiple-resistance model. A previously developed relationship between the sampling rate of the passive sampler and GOM concentrations was used to estimate dry deposition and a scaling factor of 3 was used to adjust GOM concentrations, due to underestimation by KCl-coated denuder measurements. With the scaling factor of 3, modeled deposition was in the range of results estimated from two different models settings. However, dry deposition did not correlate consistently with either model. The disagreement could be due to uncertainties associated with measurements and/or modeling, or different GOM compounds existing in the atmosphere. If the atmospheric GOM compounds are known, dry deposition velocities could be estimated more accurately. Lastly, we investigated the potential for use of a new sampling material for GOM and checked the efficiency of the passive sampler.

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Dry deposition of gaseous oxidized mercury in Western Maryland

Cited by 45 publications

References 18 publications

Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA

Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA

An assessment of atmospheric mercury in the Community Multiscale Air Quality (CMAQ) model at an urban site and a rural site in the Great Lakes Region of North America

Use of Passive Sampling Methods and Models to Understand Sources of Mercury Deposition to High Elevation Sites in the Western United States

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