A synthesis of research needs for improving the understanding of atmospheric mercury cycling

Zhang, Leiming; Lyman, Seth; Mao, Huiting; Lin, Che‐Jen; Gay, David A.; Wang, Yafei; Gustin, Mae Sexauer; Feng, Xinbin; Wania, Frank

doi:10.5194/acp-17-9133-2017

Cited by 37 publications

(26 citation statements)

References 110 publications

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“…While Hg ubiquitously exists in the natural environment, anthropogenic activities have moved previously sequestered materials (e.g., Hg in coal and metallurgical ores) into the ecosphere and increased its bioavailability [2]. Global emissions of Hg to the atmosphere are estimated to be approximately one-third from direct anthropogenic sources, approximately one-third from re-emission of previously deposited anthropogenic emissions, and about one-third from natural sources, but there are significant uncertainties in the overall amounts and proportions, as well as the spatial, temporal, and chemical distribution of emissions [3][4][5]. The concentrations of Hg in the air are usually low and they are generally not an air quality concern.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Observations of Atmospheric Speciated Mercury at a Coastal Site in the Northern Gulf of Mexico during 2007–2018

et al. 2020

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Atmospheric mercury species (gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM)), trace pollutants (O 3 , SO 2 , CO, NO, NO Y , and black carbon), and meteorological parameters have been continuously measured since 2007 at an Atmospheric Mercury Network (AMNet) site that is located on the northern coast of the Gulf of Mexico in Moss Point, Mississippi. For the data that were collected between 2007 and 2018, the average concentrations and standard deviations are 1.39 ± 0.22 ng m −3 for GEM, 5.1 ± 10.2 pg m −3 for GOM, 5.9 ± 13.0 pg m −3 for PBM, and 309 ± 407 ng m −2 wk −1 for mercury wet deposition, with interannual trends of −0.009 ng m −3 yr −1 for GEM, −0.36 pg m −3 yr −1 for GOM, 0.18 pg m −3 yr −1 for PBM, and 2.8 ng m −2 wk −1 yr −1 for mercury wet deposition. The diurnal variation of GEM shows lower concentrations in the early morning due to GEM depletion, likely due to plant uptake in high humidity events and slight elevation during the day, likely due to downward mixing to the surface of higher concentrations of GEM in the air aloft. The seasonal variation of GEM shows higher levels in winter and spring and lower levels in summer and fall. Diurnal variations of both GOM and PBM show broad peaks in the afternoon likely due to the photochemical oxidation of GEM. Seasonally, PBM measurements exhibit higher levels in winter and early spring and lower levels in summer with rising levels in fall, while GOM measurements show high levels in late spring/early summer and late fall and low levels in winter. The seasonal variation of mercury wet deposition shows higher values in summer and lower values in winter, due to larger rainfall amounts in summer than in winter. As expected, anticorrelation between mercury wet deposition and the sum of GOM and PBM, but positive correlation between mercury wet deposition and rainfall were observed. Correlation among GOM, ozone, and SO 2 suggests possible different GOM sources: direct emissions and photochemical oxidation of GEM, with the possible influence of boundary layer dynamics and seasonal variability. This study indicates that the monitoring site experiences are impacted from local and regional mercury sources as well as large scale mercury cycling phenomena.

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Section: Introductionmentioning

confidence: 99%

Long-Term Observations of Atmospheric Speciated Mercury at a Coastal Site in the Northern Gulf of Mexico during 2007–2018

et al. 2020

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“…The measurement of GOM and PBM requires detection at part-per-quadrillion (pg m −3 ) concentrations and depends currently on uncalibrated operationally defined methods with demonstrated interferences and artifacts and concomitant large uncertainty (Marusczak et al, 2017;McClure et al, 2014;Gustin et al, 2013;Lyman et al, 2010). Recent reviews (Zhang et al, 2017;Gustin et al, 2015) detail the shortcomings, difficulties, developments, and ongoing improvements needed for atmospheric RM measurements.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of cation exchange membrane performance under exposure to high Hg<sup>0</sup> and HgBr<sub>2</sub> concentrations

et al. 2019

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Reactive mercury (RM), the sum of both gaseous oxidized Hg and particulate bound Hg, is an important component of the global atmospheric mercury cycle, but measurement currently depends on uncalibrated operationally defined methods with large uncertainty and demonstrated interferences and artifacts. Cation exchange membranes (CEMs) provide a promising alternative methodology for quantification of RM, but method validation and improvements are ongoing. For the CEM material to be reliable, uptake of gaseous elemental mercury (GEM) must be negligible under all conditions and RM compounds must be captured and retained with high efficiency. In this study, the performance of CEM material under exposure to high concentrations of GEM (1.43 × 10 6 to 1.85 × 10 6 pg m −3 ) and reactive gaseous mercury bromide (HgBr 2 ∼ 5000 pg m −3 ) was explored using a custom-built mercury vapor permeation system. Quantification of total permeated Hg was measured via pyrolysis at 600 • C and detection using a Tekran ® 2537A. Permeation tests were conducted over 24 to 72 h in clean laboratory air, with absolute humidity levels ranging from 0.1 to 10 g m −3 water vapor. GEM uptake by the CEM material averaged no more than 0.004 % of total exposure for all test conditions, which equates to a non-detectable GEM artifact for typical ambient air sample concentrations. Recovery of HgBr 2 on CEM filters was on average 127 % compared to calculated total permeated HgBr 2 based on the downstream Tekran ® 2537A data. The low HgBr 2 breakthrough on the downstream CEMs (< 1 %) suggests that the elevated recoveries are more likely related to suboptimal pyrolyzer con-ditions or inefficient collection on the Tekran ® 2537A gold traps.

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“…However, the lack of an Asian continental-scale network with accessible data and long-term measurements is an important and missing piece of the mercury puzzle, particularly for countries that have signed on to the Minamata Convention. Further, data suggest that anthropogenic mercury emissions are highest in Asia [15,24,25], and fish consumption is quite high in many of these countries [26].…”

Section: Introductionmentioning

confidence: 99%

A New Monitoring Effort for Asia: The Asia Pacific Mercury Monitoring Network (APMMN)

Sheu

Gay²,

Schmeltz

et al. 2019

Atmosphere

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The Asia Pacific Mercury Monitoring Network (APMMN) cooperatively measures mercury in precipitation in a network of sites operating in Asia and the Western Pacific region. The network addresses significant data gaps in a region where mercury emission estimates are the highest globally, and available measurement data are limited. The reduction of mercury emissions under the Minamata Convention on Mercury also justifies the need for continent-wide and consistent observations that can help determine the magnitude of the problem and assess the efficacy of reductions over time. The APMMN’s primary objectives are to monitor wet deposition and atmospheric concentrations of mercury and assist partners in developing their own monitoring capabilities. Network planning began in 2012 with wet deposition sampling starting in 2014. Currently, eight network sites measure mercury in precipitation following standardized procedures adapted from the National Atmospheric Deposition Program. The network also has a common regional analytical laboratory (Taiwan), and quality assurance and data flagging procedures, which ensure the network makes scientifically valid and consistent measurements. Results from our ongoing analytical and field quality assurance measurements show minimal contamination in the network and accurate analytical analyses. We are continuing to monitor a potential concentration and precipitation volume bias under certain conditions. The average mercury concentration in precipitation was 11.3 (+9.6) ng L−1 for 139 network samples in 2018. Concentrations for individual sites vary widely. Low averages compare to the low concentrations observed on the U.S. West Coast; while other sites have average concentrations similar to the high values reported from many urban areas in China. Future APMMN goals are to (1) foster new network partnerships, (2) continue to collect, quality assure, and distribute results on the APMMN website, (3) provide training and share best monitoring practices, and (4) establish a gaseous concentration network for estimating dry deposition.

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A synthesis of research needs for improving the understanding of atmospheric mercury cycling

Cited by 37 publications

References 110 publications

Long-Term Observations of Atmospheric Speciated Mercury at a Coastal Site in the Northern Gulf of Mexico during 2007–2018

Long-Term Observations of Atmospheric Speciated Mercury at a Coastal Site in the Northern Gulf of Mexico during 2007–2018

Evaluation of cation exchange membrane performance under exposure to high Hg<sup>0</sup> and HgBr<sub>2</sub> concentrations

A New Monitoring Effort for Asia: The Asia Pacific Mercury Monitoring Network (APMMN)

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A synthesis of research needs for improving the understanding of atmospheric mercury cycling

Cited by 37 publications

References 110 publications

Long-Term Observations of Atmospheric Speciated Mercury at a Coastal Site in the Northern Gulf of Mexico during 2007–2018

Long-Term Observations of Atmospheric Speciated Mercury at a Coastal Site in the Northern Gulf of Mexico during 2007–2018

Evaluation of cation exchange membrane performance under exposure to high Hg&lt;sup&gt;0&lt;/sup&gt; and HgBr&lt;sub&gt;2&lt;/sub&gt; concentrations

A New Monitoring Effort for Asia: The Asia Pacific Mercury Monitoring Network (APMMN)

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Product

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Evaluation of cation exchange membrane performance under exposure to high Hg<sup>0</sup> and HgBr<sub>2</sub> concentrations