A Local Scale Modeling Study of Mercury Depletion Event at Canadian Arctic

Modeling Study

A modeling study was conducted on the transformation and deposition patterns of atmospheric mercury in the Canadian Arctic. One Dimensional (1-D) local scale model was used to simulate the episodic depletions of gaseous elemental mercury (GEM) after polar sunrise at Alert, Canada. The model was developed by starting with existing meteorological model (LCM-Local Climate Model) which is coupled with Canadian Aerosol Module (CAM) and then adding modules specific to atmospheric mercury chemistry. The model is able to simulate local scale transport of mercury over the entire depth of the troposphere with a basic time step of 20 min. and incorporates current knowledge of transformation reactions of atmospheric mercury species. Three mercury species Hg(O), Hg(II) and Hg(p) were considered. The developed model was applied to a portion of the Canadian Arctic region, Alert, for the month of April 2002. The model was then evaluated by comparing model estimates of mercury species concentrations with the measurement data collected in the Canadian Arctic by Meteorological Services of Canada, Downsview, Ontario. The results from this modeling study agree reasonably well with some underestimation caused by lower conversion of gaseous elemental mercury (GEM) into reactive gaseous mercury (RGM) and subsequent conversion to total particulate mercury (TPM). A sensitivity analysis was also conducted to examine the depositions of mercury species in response to changes in ozone and soot concentrations.

A Local Scale Modeling Study of Mercury Depletion Event at Canadian Arctic

10.32920/ryerson.14647020 ◽

2021 ◽

Author(s):

Minish Panchall

Keyword(s):

Measurement Data ◽

Canadian Arctic ◽

Elemental Mercury ◽

Local Scale ◽

Atmospheric Mercury ◽

Scale Model ◽

Mercury Species ◽

Time Step ◽

Modeling Study

Simulation of atmospheric mercury depletion events (AMDEs) during polar springtime using the MECCA box model

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-7165-2008 ◽

2008 ◽

Vol 8 (23) ◽

pp. 7165-7180 ◽

Cited By ~ 35

Author(s):

Z.-Q. Xie ◽

R. Sander ◽

U. Pöschl ◽

F. Slemr

Keyword(s):

Aqueous Phase ◽

Ozone Depletion ◽

Elemental Mercury ◽

Atmospheric Mercury ◽

Box Model ◽

Rate Coefficients ◽

Mercury Species ◽

Phase Reaction ◽

Sea Salt Aerosol

Abstract. Atmospheric mercury depletion events (AMDEs) during polar springtime are closely correlated with bromine-catalyzed tropospheric ozone depletion events (ODEs). To study gas- and aqueous-phase reaction kinetics and speciation of mercury during AMDEs, we have included mercury chemistry into the box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere), which enables dynamic simulation of bromine activation and ODEs. We found that the reaction of Hg with Br atoms dominates the loss of gaseous elemental mercury (GEM). To explain the experimentally observed synchronous depletion of GEM and O3, the reaction rate of Hg+BrO has to be much lower than that of Hg+Br. The synchronicity is best reproduced with rate coefficients at the lower limit of the literature values for both reactions, i.e. kHg+Br≈3×10−13 and kHg+BrO≤1×10−15 cm3 molecule−1 s−1, respectively. Throughout the simulated AMDEs, BrHgOBr was the most abundant reactive mercury species, both in the gas phase and in the aqueous phase. The aqueous-phase concentrations of BrHgOBr, HgBr2, and HgCl2 were several orders of magnitude larger than that of Hg(SO3)22−. Considering chlorine chemistry outside depletion events (i.e. without bromine activation), the concentration of total divalent mercury in sea-salt aerosol particles (mostly HgCl42−) was much higher than in dilute aqueous droplets (mostly Hg(SO3)22−), and did not exhibit a diurnal cycle (no correlation with HO2 radicals).

Simulation of atmospheric mercury depletion events (AMDEs) during polar springtime using the MECCA box model

10.5194/acpd-8-13197-2008 ◽

2008 ◽

Vol 8 (4) ◽

pp. 13197-13232 ◽

Cited By ~ 1

Author(s):

Z.-Q. Xie ◽

R. Sander ◽

U. Pöschl ◽

F. Slemr

Keyword(s):

Aqueous Phase ◽

Ozone Depletion ◽

Elemental Mercury ◽

Atmospheric Mercury ◽

Box Model ◽

Rate Coefficients ◽

Mercury Species ◽

Phase Reaction ◽

Sea Salt Aerosol

Abstract. Atmospheric mercury depletion events (AMDEs) during polar springtime are closely correlated with bromine-catalyzed tropospheric ozone depletion events (ODEs). To study gas- and aqueous-phase reaction kinetics and speciation of mercury during AMDEs, we have included mercury chemistry into the box model MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere), which enables dynamic simulation of bromine activation and ODEs. We found that the reaction of Hg with Br atoms dominates the loss of gaseous elemental mercury (GEM). To explain the experimentally observed synchronous destruction of Hg and O3, the reaction rate of Hg+BrO has to be much lower than that of Hg+Br. The synchronicity is best reproduced with rate coefficients at the lower limit of the literature values for both reactions, i.e. kHg+Br≈3×10-13 and kHg+BrO≤1×10-15cm3 mol-1 s-1, respectively. Throughout the simulated AMDEs, BrHgOBr was the most abundant reactive mercury species, both in the gas phase and in the aqueous phase. The aqueous phase concentrations of BrHgOBr, HgBr2, and HgCl2 were several orders of magnitude larger than that of Hg(SO3)2-2. Considering chlorine chemistry outside depletion events (i.e. without bromine activation), the concentration of total divalent mercury in sea-salt aerosol particles (mostly HgCl2) was much higher than in dilute aqueous droplets (mostly Hg(SO3)2-2), and did not exhibit a diurnal cycle (no correlation with HO2 radicals).

A 2 year record of atmospheric mercury species at a background Southern Hemisphere station on Amsterdam Island

10.5194/acpd-14-14439-2014 ◽

2014 ◽

Vol 14 (10) ◽

pp. 14439-14470

Author(s):

H. Angot ◽

M. Barret ◽

O. Magand ◽

M. Ramonet ◽

A. Dommergue

Keyword(s):

Indian Ocean ◽

Southern Hemisphere ◽

Marine Boundary Layer ◽

Elemental Mercury ◽

Atmospheric Mercury ◽

Southern Indian Ocean ◽

Observation System ◽

Mercury Species ◽

Back Trajectories ◽

Gaseous Elemental Mercury

Abstract. Scarcity of mercury species records in the Southern Hemisphere is a critical weak point for the development of appropriate modeling and regulation scenarios. Under the framework of the "Global Mercury Observation System" (GMOS) project, a monitoring station has been set up on Amsterdam Island (37°48' S, 77°34' E) in the remote southern Indian Ocean. For the first time in the Southern Hemisphere, a 2 year record of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound mercury (PBM) is presented. GEM concentrations were remarkably steady (1.03 ± 0.08 pg m−3) while RGM and PBM concentrations were very low and exhibited a strong variability (mean: 0.34 pg m−3 [range: 0.28–4.07 pg m−3] and mean: 0.67 pg m−3 [range: 0.28–12.67 pg m−3], respectively). Despite the remoteness of the island, wind sector analysis, air mass back trajectories and the observation of radonic storms highlighted a long-range contribution from the southern African continent to the GEM and PBM budgets in winter during the biomass burning season. Lowest concentrations of GEM were associated with southerly polar and marine air masses from the remote southern Indian Ocean. This unique dataset provides new baseline GEM concentrations in the Southern Hemisphere mid-latitudes for further modeling studies, while mercury speciation along with upcoming wet deposition data will help improving our understanding of mercury cycle in the marine boundary layer.

Measurements of atmospheric mercury species at a German rural background site from 2009 to 2011 – methods and results

Environmental Chemistry ◽

10.1071/en12107 ◽

2013 ◽

Vol 10 (2) ◽

pp. 102 ◽

Cited By ~ 27

Author(s):

Andreas Weigelt ◽

Christian Temme ◽

Elke Bieber ◽

Andreas Schwerin ◽

Maik Schuetze ◽

...

Keyword(s):

Elemental Mercury ◽

Atmospheric Mercury ◽

Pollution Monitoring ◽

Mercury Species ◽

Total Gaseous Mercury ◽

Rural Background ◽

Background Site ◽

Gaseous Mercury

Environmental context Mercury is a very hazardous substance for human and environmental health. Systematic long-term direct measurements in the atmosphere can provide valuable information about the effect of emission controls on the global budget of atmospheric mercury, and offer insight into source–receptor transboundary transport of mercury. A complete setup for the measurement of the four most relevant atmospheric mercury species (total gaseous mercury, gaseous oxidised mercury, particle-bound mercury, and gaseous elemental mercury) has been operating at the rural background site of Waldhof, Germany, since 2009. We present the dataset for 2009–2011, the first full-speciation time series for atmospheric mercury reported in Central Europe. Abstract Measurements of mercury species started in 2009 at the air pollution monitoring site ‘Waldhof’ of the German Federal Environmental Agency. Waldhof (52°48′N, 10°45′E) is a rural background site located in the northern German lowlands in a flat terrain, 100km south-east of Hamburg. The temporally highly resolved measurements of total gaseous mercury (TGM), gaseous oxidised mercury (GOM), particle-bound mercury (PBMPM2.5, with particulate matter of a diameter of ≤2.5µm) and gaseous elemental mercury (GEM) cover the period from 2009 to 2011. The complete measurement procedure turned out to be well applicable to detect GOM and PBMPM2.5 levels in the range of 0.4 to 65pgm–3. As the linearity of the analyser was proven to be constant over orders of magnitude, even larger concentrations can be measured accurately. The 3-year median concentration of GEM is found to be 1.61ngm–3, representing typical northern hemispheric background concentrations. With 6.3pgm–3, the 3-year average concentration of PBMPM2.5 is found to be approximately six times higher than the 3-year average GOM concentration. During winter the PBMPM2.5 concentration is on average twice as high as the PBMPM2.5 summer concentration, whereas the GOM concentration shows no clear seasonality. However, on a comparatively low level, a significant diurnal cycle is shown for GOM concentrations. This cycle is most likely related to photochemical oxidation mechanisms. Comparison with selected North American long-term mercury speciation datasets shows that the Waldhof 3-year median speciated mercury data represent typical rural background values.

Natural and anthropogenic atmospheric mercury in the European Arctic: a speciation study

10.5194/acpd-10-27255-2010 ◽

2010 ◽

Vol 10 (11) ◽

pp. 27255-27281

Author(s):

A. O. Steen ◽

T. Berg ◽

A. P. Dastoor ◽

D. A. Durnford ◽

L. R. Hole ◽

...

Keyword(s):

Elemental Mercury ◽

Atmospheric Mercury ◽

Mercury Species ◽

In Situ Oxidation ◽

Air Masses ◽

Complete Dataset ◽

Speciation Study ◽

European Arctic

Abstract. It is agreed that gaseous elemental mercury (GEM) is converted to reactive gaseous mercury (RGM) during springtime Atmospheric Mercury Depletion Event (AMDE). RGM is associated with aerosols (PHg) provided that there are sufficient aerosols available for the conversion from RGM to PHg to occur. This study reports the longest time series of GEM, RGM and PHg concentrations from a European Arctic site. From 27 April 2007 until 31 December 2008 composite GEM, RGM and PHg measurements were conducted in Ny-Ålesund (78°54' N, 11°53' E). The average concentrations of the complete dataset were 1.62±0.3 ng m−3, 8±13 pgm−3 and 8±25 pgm−3 for GEM, RGM and PHg, respectively. The study revealed a clear seasonal distribution of GEM, RGM and PHg previously undiscovered. For the complete dataset the atmospheric mercury distribution was 99% GEM, whereas RGM and PHg constituted <1%. Increased PHg concentration occurred exclusively from March through April, and constituted on average 75% of the reactive mercury species in the respective period. RGM was suggested as the precursor for the PHg existence, but long range transportation of PHg has to be taken into consideration. Surprisingly, RGM was not solely formed during the spring AMDE season. Environment Canada's Global/Regional Atmospheric Heavy Metal model (GRAHM) suggested that in situ oxidation of GEM by ozone may be producing the increased RGM concentrations from March through August. Most likely, in situ oxidation of GEM by BrO produced the observed RGM from March through August. The AMDEs occurred from late March until mid June and were thought to be of non-local origin, with GEM being transported to the study site by a wide variety of air masses. With some exceptions, no clear meteorological regime was associated with the GEM, RGM and PHg concentrations.

Impacts of Large-Scale Circulation on Urban Ambient Concentrations of Gaseous Elemental Mercury in New York, USA

10.5194/acp-2017-176 ◽

2017 ◽

Cited By ~ 1

Author(s):

Huiting Mao ◽

Dolly Hall ◽

Zhuyun Ye ◽

Ying Zhou ◽

Dirk Felton ◽

...

Keyword(s):

New York ◽

North American ◽

Large Scale ◽

Measurement Data ◽

Elemental Mercury ◽

Urban Site ◽

Large Scale Circulation ◽

The North ◽

The Impact

Abstract. The impact of large-scale circulation on urban gaseous elemental mercury (GEM) was investigated through analysis of 2008–2015 measurement data from an urban site in New York City (NYC), New York, USA. Distinct annual cycles were observed in 2009–2010 with mixing ratios in warm seasons (i.e. spring–summer) 10–20 ppqv (~ 10 %–25 %) higher than in cool seasons (i.e. fall–winter). This annual cycle was disrupted in 2011 by an anomalously strong influence of the North American trough in that warm season and was reproduced in 2014 with annual amplitude enhanced up to ~ 70 ppqv associated with a particularly strong Bermuda High. North American trough axis index (TAI) and intensity index (TII) were used to characterize the effect of the North American trough on NYC GEM especially in winter and summer. The intensity and position of the Bermuda High had a significant impact on GEM in warm seasons supported by a strong correlation (r reaching 0.96, p

Speciated Atmospheric Mercury during Haze and Non-haze Days in an Inland City in China

10.5194/acp-2016-467 ◽

2016 ◽

Author(s):

Qianqian Hong ◽

Zhouqing Xie ◽

Cheng Liu ◽

Feiyue Wang ◽

Pinhua Xie ◽

...

Keyword(s):

Elemental Mercury ◽

Atmospheric Mercury ◽

Central China ◽

Mercury Emissions ◽

Enhanced Production ◽

Mercury Transport ◽

Haze Pollution ◽

The Mean ◽

Haze Days

Abstract. Long-term continuous measurements of speciated atmospheric mercury were conducted at Hefei, a mid-latitude inland city in east central China, from July 2013 to June 2014. The mean concentrations (± standard deviation) of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound mercury (PBM) were 3.95 ± 1.93 ng m−3, 2.49 ± 2.41 pg m−3 and 23.3 ± 90.8 pg m−3, respectively, during non-haze days, and 4.74 ± 1.62 ng m−3, 4.32 ± 8.36 pg m−3 and 60.2 ± 131.4 pg m−3, respectively, during haze days. Potential source contribution function (PSCF) analysis suggested that the atmospheric mercury pollution during haze days was caused primarily by local mercury emissions, instead of via long-range mercury transport. In addition, the disadvantageous diffussion during haze days will also enhance the level of atmospheric mercury. Compared to the GEM and RGM, change in PBM was more sensitive to the haze pollution. The mean PBM concentration during haze days was 2.5 times that during non-haze days due to elevated concentrations of particulate matter. A remarkable seasonal trend in PBM was observed with concentration decreasing in the following order in response to the frequency of haze days: autumn, winter, spring, summer. A distinct diurnal relationship was found between GEM and RGM during haze days, with the peak values of RGM coinciding with the decline in GEM. Using HgOH as an intermediate product during GEM oxidation, our results suggest that NO2 aggregation with HgOH could explain the enhanced production of RGM during the daytime in haze days. Increasing level of NOx will potentially accelerate the oxidation of GEM despite the decrease of solar radiation.

Gaseous mercury in coastal urban areas

Environmental Chemistry ◽

10.1071/en10088 ◽

2010 ◽

Vol 7 (6) ◽

pp. 537 ◽

Cited By ~ 3

Author(s):

Anne L. Soerensen ◽

Henrik Skov ◽

Matthew S. Johnson ◽

Marianne Glasius

Keyword(s):

Urban Areas ◽

Marine Boundary Layer ◽

Elemental Mercury ◽

Atmospheric Mercury ◽

Mercury Deposition ◽

Mercury Emissions ◽

Gaseous Mercury ◽

Range Transport ◽

Aquatic Food

Environmental context Mercury is a neurotoxin that bioaccumulates in the aquatic food web. Atmospheric emissions from urban areas close to the coast could cause increased local mercury deposition to the ocean. Our study adds important new data to the current limited knowledge on atmospheric mercury emissions and dynamics in coastal urban areas. Abstract Approximately 50% of primary atmospheric mercury emissions are anthropogenic, resulting from e.g. emission hotspots in urban areas. Emissions from urban areas close to the coast are of interest because they could increase deposition loads to nearby coastal waters as well as contribute to long range transport of mercury. We present results from measurements of gaseous elemental mercury (GEM) and reactive gaseous mercury (RGM) in 15 coastal cities and their surrounding marine boundary layer (MBL). An increase of 15–90% in GEM concentration in coastal urban areas was observed compared with the remote MBL. Strong RGM enhancements were only found in two cities. In urban areas with statistically significant GEM/CO enhancement ratios, slopes between 0.0020 and 0.0087 ng m–3 ppb–1 were observed, which is consistent with other observations of anthropogenic enhancement. The emission ratios were used to estimate GEM emissions from the areas. A closer examination of data from Sydney (Australia), the coast of Chile, and Valparaiso region (Chile) in the southern hemisphere, is presented.

A synthesis of atmospheric mercury depletion event chemistry linking atmosphere, snow and water

10.5194/acpd-7-10837-2007 ◽

2007 ◽

Vol 7 (4) ◽

pp. 10837-10931 ◽

Cited By ~ 19

Author(s):

A. Steffen ◽

T. Douglas ◽

M. Amyot ◽

P. Ariya ◽

K. Aspmo ◽

...

Keyword(s):

Sea Ice ◽

Current Knowledge ◽

Kinetic Studies ◽

Elemental Mercury ◽

Atmospheric Mercury ◽

The Arctic ◽

Polar Regions ◽

Environmental Media ◽

History Of

Abstract. It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM) occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere; however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg). This phenomenon is termed atmospheric mercury depletion events (AMDEs) and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review the history of Hg in Polar Regions, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the roles that the snow pack, oceans, fresh water and the sea ice play in the cycling of Hg are presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the deposited Hg does not remain in the same form in the snow. Kinetic studies undertaken have demonstrated that bromine is the major oxidant depleting Hg in the atmosphere. Modeling results demonstrate that there is a significant deposition of Hg to Polar Regions as a result of AMDEs. Models have also shown that Hg is readily transported to the Arctic from source regions, at times during springtime when this environment is actively transforming Hg from the atmosphere to the snow and ice surfaces. The presence of significant amounts of methyl Hg in snow in the Arctic surrounding AMDEs is important because this species is the link between the environment and impacts to wildlife and humans. Further, much work on methylation and demethylation processes have occurred but are not yet fully understood. Recent changes in the climate and sea ice cover in Polar Regions are likely to have strong effects on the cycling of Hg in this environment; however more research is needed to understand Hg processes in order to formulate meaningful predictions of these changes. Mercury, Atmospheric mercury depletion events (AMDE), Polar, Arctic, Antarctic, Ice