Bromine-induced oxidation of mercury in the mid-latitude atmosphere

Obrist, Daniel; Tas, Eran; Peleg, Mordechai; Matveev, V.; Faïn, Xavier; Asaf, David; Luria, Menachem

doi:10.1038/ngeo1018

Cited by 138 publications

(123 citation statements)

References 31 publications

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“…However, in the Arctic (and Antarctic) this partitioning changes during the spring months; at Alert for example, to 88.5 % GEM, 4.5 % RGM and 7 % PHg (using the mean Alert mercury concentration data from 2002 to 2011) or 95.6 % GEM, 2 % RGM and 2.4 % PHg (using median concentrations). It is well known that a series of photochemically initiated reactions can oxidize GEM to an Hg(II) inorganic species (Simpson et al, 2007;Ariya et al, 2008;Obrist et al, 2011). These reactions result in atmospheric mercury depletion events (AMDEs) and refer to the depletion of GEM from the troposphere.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric mercury speciation and mercury in snow over time at Alert, Canada

et al. 2014

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Abstract. Ten years of atmospheric mercury speciation data and 14 years of mercury in snow data from Alert, Nunavut, Canada, are examined. The speciation data, collected from 2002 to 2011, includes gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM). During the winter-spring period of atmospheric mercury depletion events (AMDEs), when GEM is close to being completely depleted from the air, the concentration of both PHg and RGM rise significantly. During this period, the median concentrations for PHg is 28.2 pgm−3 and RGM is 23.9 pgm−3, from March to June, in comparison to the annual median concentrations of 11.3 and 3.2 pgm−3 for PHg and RGM, respectively. In each of the ten years of sampling, the concentration of PHg increases steadily from January through March and is higher than the concentration of RGM. This pattern begins to change in April when the levels of PHg peak and RGM begin to increase. In May, the high PHg and low RGM concentration regime observed in the early spring undergoes a transition to a regime with higher RGM and much lower PHg concentrations. The higher RGM concentration continues into June. The transition is driven by the atmospheric conditions of air temperature and particle availability. Firstly, a high ratio of the concentrations of PHg to RGM is reported at low temperatures which suggests that oxidized gaseous mercury partitions to available particles to form PHg. Prior to the transition, the median air temperature is −24.8 °C and after the transition the median air temperature is −5.8 °C. Secondly, the high PHg concentrations occur in the spring when high particle concentrations are present. The high particle concentrations are principally due to Arctic haze and sea salts. In the snow, the concentrations of mercury peak in May for all years. Springtime deposition of total mercury to the snow at Alert peaks in May when atmospheric conditions favour higher levels of RGM. Therefore, the conditions in the atmosphere directly impact when the highest amount of mercury will be deposited to the snow during the Arctic spring.

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Section: Introductionmentioning

confidence: 99%

Atmospheric mercury speciation and mercury in snow over time at Alert, Canada

et al. 2014

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“…However, there is very real uncertainty in the understanding of the dominant chemical pathway for oxidation of Hg 0 to RHg, and many components of the mercury budget remain uncertain (Calvert and Lindberg, 2005;Hynes et al, 2009). In particular, recent model and observational studies have suggested that the bromine oxidation pathway may be important in the mid-latitudes Obrist et al, 2010).…”

Section: Introductionmentioning

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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“…Likewise, GOM may also be formed in the troposphere by oxidation of GEM. The GOM formation is likely to be caused by a bromine-driven photolytic oxidation process (Donohoue et al, 2006;Obrist et al, 2011). GOM is probably formed at a slow rate in the atmosphere and, due to its solubility, it is efficiently being scavenged by atmospheric cloud droplets and, therefore, has a short residence time in the atmosphere.…”

Section: Background and Polluted Air Massesmentioning

confidence: 99%

Airborne mercury species at the Råö background monitoring site in Sweden: distribution of mercury as an effect of long-range transport

Wängberg¹,

Mastromonaco²,

Munthe³

et al. 2016

Atmos. Chem. Phys.

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Abstract. Within the EU-funded project, Global Mercury Observation System (GMOS) airborne mercury has been monitored at the background Råö measurement site on the western coast of Sweden from mid-May 2012 to the beginning of July 2013 and from the beginning of February 2014 to the end of May 2015. The following mercury species/fractions were measured: gaseous elemental mercury (GEM), particulate bound mercury (PBM) and gaseous oxidised mercury (GOM) using the Tekran measurement system. The mercury concentrations measured at the Råö site were found to be low in comparison to other, comparable, European measurement sites. A back-trajectory analysis to study the origin of air masses reaching the Råö site was performed. Due to the remote location of the Råö measurement station it receives background air about 60 % of the time. However, elevated mercury concentrations arriving with air masses coming from the south-east are noticeable. GEM and PBM concentrations show a clear annual variation with the highest values occurring during winter, whereas the highest concentrations of GOM were obtained in spring and summer. An evaluation of the diurnal pattern of GOM, with peak concentrations at midday or in the early afternoon, which often is observed at remote places, shows that it is likely to be driven by local meteorology in a similar way to ozone. Evidence that a significant part of the GOM measured at the Råö site has been formed in free tropospheric air is presented.

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Bromine-induced oxidation of mercury in the mid-latitude atmosphere

Cited by 138 publications

References 31 publications

Atmospheric mercury speciation and mercury in snow over time at Alert, Canada

Atmospheric mercury speciation and mercury in snow over time at Alert, Canada

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

Airborne mercury species at the Råö background monitoring site in Sweden: distribution of mercury as an effect of long-range transport

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