The influence of ozone on atmospheric emissions of gaseous elemental mercury and reactive gaseous mercury from substrates

Abstract. The chemical cycling and spatiotemporal distribution of mercury in the troposphere is poorly understood. We measured gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate mercury (HgP) along with CO, ozone, aerosols, and meteorological variables at Storm Peak Laboratory at an elevation of 3200 m a.s.l., in Colorado, from 28 April to 1 July 2008. The mean mercury concentrations were 1.6 ng m−3 (GEM), 20 pg m−3 (RGM) and 9 pg m−3 (HgP). We observed eight events of strongly enhanced atmospheric RGM levels with maximum concentrations up to 135 pg m−3. RGM enhancement events were unrelated to daytime/nighttime patterns and lasted for long time periods of 2 to 6 days. During seven of these events, RGM was inversely correlated to GEM (RGM/GEM regression slope ~ −0.1), but did not exhibit correlations with ozone, carbon monoxide, or aerosol concentrations. Relative humidity was the dominant factor affecting RGM levels with high RGM levels always present whenever relative humidity was below 40 to 50%. We conclude that RGM enhancements observed at Storm Peak Laboratory were not induced by pollution events and were related to oxidation of tropospheric GEM, but the mechanism remain unclear. Based on backtrajectory analysis and a lack of mass balance between RGM and GEM, we propose that in situ production of RGM may have occurred in some distance allowing for scavenging and/or deposition of some RGM prior to reaching the laboratory, and that GEM oxidation is an important tropospheric Hg sink. Our observations provide evidence that the tropospheric pool of mercury is frequently enriched in divalent mercury and that high RGM levels are not limited to the upper troposphere.

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Two new sources of reactive gaseous mercury in the free troposphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-29203-2012 ◽

2012 ◽

Vol 12 (11) ◽

pp. 29203-29233 ◽

Cited By ~ 2

Author(s):

H. Timonen ◽

J. L. Ambrose ◽

D. A. Jaffe

Keyword(s):

Source Region ◽

Elemental Mercury ◽

Anthropogenic Pollution ◽

Atmospheric Mercury ◽

Free Troposphere ◽

Mercury Deposition ◽

Gaseous Elemental Mercury ◽

Reactive Gaseous Mercury ◽

Gaseous Mercury ◽

The Pacific

Abstract. Mercury (Hg) is a neurotoxin that bioaccumulates in the food chain. Mercury is emitted to the atmosphere primarily in its elemental form, which has a long lifetime allowing global transport. It is known that atmospheric oxidation of gaseous elemental mercury (GEM) generates reactive gaseous mercury (RGM) which plays an important role in the atmospheric mercury cycle by enhancing the rate of mercury deposition to ecosystems. However, the primary GEM oxidants, and the sources and chemical composition of RGM are poorly known. Using speciated mercury measurements conducted at the Mt. Bachelor Observatory since 2005 we present two previously unidentified sources of RGM to the free troposphere (FT). Firstly, we observed elevated RGM concentrations, large RGM/GEM-ratios, and anti-correlation between RGM and GEM during Asian long-rang transport events, demonstrating that RGM is formed from GEM by in-situ oxidation in some anthropogenic pollution plumes in the FT. During the Asian pollution events the measured RGM/GEM-ratios reached peak values, up to ~0.20, which are significantly larger than ratios typically measured (RGM/GEM < 0.05) in the Asian source region. Secondly, we observed very high RGM levels – the highest reported in the FT – in clean air masses that were processed upwind of Mt. Bachelor Observatory over the Pacific Ocean. The high RGM concentrations (up to 700 pg m−3), high RGM/GEM-ratios (up to 1), and very low ozone levels during these events provide the first observational evidence indicating significant GEM oxidation in the lower FT. The identification of these processes changes our conceptual understanding of the formation and distribution of oxidized Hg in the global atmosphere.

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Measurement of Particulate Bound Mercury, Gaseous Elemental Mercury, and Reactive Gaseous Mercury Concentrations by Using an Ambient Air Mercury Collection System

Environmental Forensics ◽

10.1080/15275922.2015.1091401 ◽

2015 ◽

Vol 16 (4) ◽

pp. 305-309 ◽

Cited By ~ 1

Author(s):

Guor-Cheng Fang ◽

Yu-Chen Kuo ◽

Yuan-Jie Zhuang ◽

Meng-Hsien Cho

Keyword(s):

Elemental Mercury ◽

Ambient Air ◽

Collection System ◽

Gaseous Elemental Mercury ◽

Reactive Gaseous Mercury ◽

Gaseous Mercury

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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 Elemental Mercury ◽

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.

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Inverse modelling for mercury over Europe

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-6-795-2006 ◽

2006 ◽

Vol 6 (1) ◽

pp. 795-838 ◽

Cited By ~ 1

Author(s):

Y. Roustan ◽

M. Bocquet

Keyword(s):

Boundary Conditions ◽

Emission Inventory ◽

Transport Model ◽

Fate And Transport ◽

Elemental Mercury ◽

Regional Model ◽

Inverse Modelling ◽

Gaseous Elemental Mercury ◽

Gaseous Mercury ◽

Mercury Monitoring

Abstract. The fate and transport of mercury over Europe is studied using a regional Eulerian transport model. Because gaseous elemental mercury is a long-lived species in the atmosphere, boundary conditions must be properly taken into account. Ground measurements of gaseous mercury are very sensitive to the uncertainties attached to those forcing conditions. Inverse modelling can help to constrain the forcing fields and help to improve the predicted mercury concentrations. More generally, it allows to reduce the weaknesses of a regional model against a global or hemispherical model for such diffuse trace constituent. Adjoint techniques are employed to relate rigorously and explicitly the measurements to the forcing fields. This way, the inverse problem is clearly defined. Using EMEP measurements of gaseous mercury and performing the inversions, it is shown that boundary conditions can be improved significantly as well as the forecast concentrations. Using inverse modelling to improve the emission inventory is however much more difficult since there are currently not enough mercury monitoring stations, and their location far from Europe centre.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-6273-2011 ◽

2011 ◽

Vol 11 (13) ◽

pp. 6273-6284 ◽

Cited By ~ 17

Author(s):

A. O. Steen ◽

T. Berg ◽

A. P. Dastoor ◽

D. A. Durnford ◽

O. Engelsen ◽

...

Keyword(s):

Elemental Mercury ◽

Atmospheric Mercury ◽

Seasonal Distribution ◽

The Arctic ◽

Mercury Distribution ◽

Gaseous Elemental Mercury ◽

Reactive Gaseous Mercury ◽

Complete Dataset ◽

European Arctic ◽

Non Local

Abstract. Gaseous elemental mercury (GEM) is converted to reactive gaseous mercury (RGM) during springtime Atmospheric Mercury Depletion Events (AMDE). This study reports the longest time series of GEM, RGM and particle-bound mercury (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 1.6 ± 0.3 ng m−3, 8 ± 13 pg m−3 and 8 ± 25 pg m−3 for GEM, RGM and PHg, respectively. For the complete dataset the atmospheric mercury distribution was 99 % GEM, whereas RGM and PHg constituted <1 %. The study revealed a seasonal distribution of GEM, RGM and PHg previously undiscovered in the Arctic. Increased concentrations of RGM were observed during the insolation period from March through August, while increased PHg concentrations occurred almost exclusively during the spring AMDE period in March and April. The elevated RGM concentrations suggest that atmospheric RGM deposition also occurs during the polar summer. RGM was suggested as the precursor for the PHg existence, but long range transportation of PHg has to be taken into consideration. Still there remain gaps in the knowledge of how RGM and PHg are related in the environment. RGM and PHg accounted for on average about 10 % of the depleted GEM during AMDEs. Although speculative, the fairly low RGM and PHg concentrations supported by the predominance of PHg with respect to RGM and no clear meteorological regime associated with these AMDEs would all suggest the events to be of non-local origin. With some exceptions, no clear meteorological regime was associated with the GEM, RGM and PHg concentrations throughout the year.

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Studies of mercury species in the atomosphere in downtown Toronto

10.32920/ryerson.14649438 ◽

2021 ◽

Author(s):

Xinjie Song

Keyword(s):

Meteorological Parameters ◽

Inorganic Mercury ◽

Elemental Mercury ◽

Ambient Air ◽

Temporal Variations ◽

Anthropogenic Sources ◽

Mercury Species ◽

Gaseous Elemental Mercury ◽

Reactive Gaseous Mercury ◽

Mean Concentration

This study had been carried out in downtown Toronto from December 2003 to November 2004. Gaseous elemental mercury (GEM), reactive gaseous mercury (RGM, also called gaseous oxidized inorganic mercury, GOIM) and mercury associated with particles having size (PM<2.5) were simultaneously measured using Tekran mercury speciation unit. Mean concentration, standard deviation and distribution of GEM, PM<2.5 and RGM were 4.52 +/- 3.13 ng m⁻³ (98.7%), 21.51 +/- 16.35 pg m⁻³ (0.5%) and 14.19 +/- 13.24 pg m⁻³ (0.3%), respectively. Local and regional anthropogenic sources are believed to contribute [to] the elevated value and high temporal variations. Overall, the mercury species concentrations are lower in winter than in the other three seasons. Nighttime GEM, PM<2.5 and RGM concentrations are higher than those of daytime. Correlation analysis was conducted between each mercury species and the meteorological parameters (i.e., surface ambient air temperature, relative humidity, wind direction), as well as among the mercury species in this study.

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In-situ and Denuder Based Measurements of Elemental and Reactive Gaseous Mercury with Analysis by Laser-Induced Fluorescence. Results from the Reno Atmospheric Mercury Intercomparison Experiment

10.5194/acp-2016-446 ◽

2016 ◽

Author(s):

Anthony J. Hynes ◽

Stephanie Everhart ◽

Dieter Bauer ◽

James Remeika ◽

Cheryl Tatum Ernest

Keyword(s):

Single Photon ◽

Thermal Dissociation ◽

Elemental Mercury ◽

Laser Induced Fluorescence ◽

Atmospheric Mercury ◽

Substantial Contribution ◽

Gaseous Elemental Mercury ◽

Gaseous Mercury ◽

The University

Abstract. The University of Miami (UM) deployed a sequential two photon laser-induced fluorescence (2P-LIF) instrument for the in-situ measurement of gaseous elemental mercury, Hg(0), during the Reno Atmospheric Mercury Intercomparison Experiment (RAMIX) campaign. A number of extended sampling experiments, typically lasting 6–8 hours but on one occasion extending to ~ 24 hours, were conducted allowing the 2P-LIF measurements of Hg(0) concentrations to be compared with two independently operated instruments using gold amalgamation sampling coupled with Cold Vapor Atomic Fluorescence Spectroscopic (CVAFS) analysis. At the highest temporal resolution, ~ 5 minute samples, the three instruments measured concentrations that agreed to within 10–25 %. Measurements of total gaseous mercury (TGM) were made by using pyrolysis to convert total oxidized mercury (TOM) to Hg(0). TOM was then obtained by difference. Variability in the ambient Hg(0) concentration limited our sensitivity for measurement of ambient TOM using this approach. In addition, manually sampled KCl coated annular denuders were deployed and analyzed using thermal dissociation coupled with single photon LIF detection of Hg(0). The TOM measurements obtained were normally consistent with KCl denuder measurements obtained with two Tekran speciation systems and with the manual KCl denuder measurements but with very large uncertainty. They were typically lower than measurements reported by the University of Washington (UW) Detector for Oxidized Hg Species (DOHGS) system. The ability of the 2P-LIF pyrolysis system to measure TGM was demonstrated during one of the manifold HgBr2 spikes but the results did not agree well with those reported by the DOHGS system. We suggest that instrumental artifacts make a substantial contribution to the discrepancies in the reported measurements over the course of the RAMIX campaign. This suggests that caution should be used in drawing significant implications for the atmospheric cycling of mercury.

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Inverse modelling for mercury over Europe

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-3085-2006 ◽

2006 ◽

Vol 6 (10) ◽

pp. 3085-3098 ◽

Cited By ~ 20

Author(s):

Y. Roustan ◽

M. Bocquet

Keyword(s):

Boundary Conditions ◽

Emission Inventory ◽

Transport Model ◽

Fate And Transport ◽

Elemental Mercury ◽

Regional Model ◽

Inverse Modelling ◽

Gaseous Elemental Mercury ◽

Gaseous Mercury ◽

Mercury Monitoring

Abstract. The fate and transport of mercury over Europe is studied using a regional Eulerian transport model. Because gaseous elemental mercury is a long-lived species in the atmosphere, boundary conditions must be properly taken into account. Ground measurements of gaseous mercury are very sensitive to the uncertainties attached to those forcing conditions. Inverse modelling can help to constrain the forcing fields and help to improve the predicted mercury concentrations. More generally, it allows to reduce the weaknesses of a regional model against a global or hemispherical model for such diffuse trace constituent. Adjoint techniques are employed to relate rigorously and explicitly the measurements to the forcing fields. This way, the inverse problem is clearly defined. Using EMEP measurements of gaseous mercury and performing the inversions, it is shown that boundary conditions can be improved significantly as well as the forecast concentrations. Using inverse modelling to improve the emission inventory is however much more difficult. Indeed, there are currently not enough mercury monitoring stations, and they are located far away from the center of Europe.

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