scholarly journals Inverse modelling for mercury over Europe

2006 ◽  
Vol 6 (1) ◽  
pp. 795-838 ◽  
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.

scholarly journals Inverse modelling for mercury over Europe

2006 ◽  
Vol 6 (10) ◽  
pp. 3085-3098 ◽  
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.

Gaseous mercury in coastal urban areas

2010 ◽  
Vol 7 (6) ◽  
pp. 537 ◽  
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.

Global Concentrations of Gaseous Elemental Mercury and Reactive Gaseous Mercury in the Marine Boundary Layer

2010 ◽  
Vol 44 (19) ◽  
pp. 7425-7430 ◽  
Author(s):  
Anne L. Soerensen ◽  
Henrik Skov ◽  
Daniel J. Jacob ◽  
Britt T. Soerensen ◽  
Matthew S. Johnson
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Elemental Mercury ◽  
Gaseous Elemental Mercury ◽  
Reactive Gaseous Mercury ◽  
Gaseous Mercury

scholarly journals High levels of reactive gaseous mercury observed at a high elevation research laboratory in the Rocky Mountains

2009 ◽  
Vol 9 (4) ◽  
pp. 15641-15671 ◽  
Author(s):  
X. Faïn ◽  
D. Obrist ◽  
A. G. Hallar ◽  
I. McCubbin ◽  
T. Rahn
Keyword(s):  
Relative Humidity ◽  
Elemental Mercury ◽  
High Elevation ◽  
Dominant Factor ◽  
Gaseous Elemental Mercury ◽  
Reactive Gaseous Mercury ◽  
Gaseous Mercury ◽  
Long Time ◽  
Chemical Cycling

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.

scholarly journals Two new sources of reactive gaseous mercury in the free troposphere

2012 ◽  
Vol 12 (11) ◽  
pp. 29203-29233 ◽  
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.

scholarly journals 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

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.

scholarly journals Gaseous elemental mercury depletion events observed at Cape Point during 2007–2008

2010 ◽  
Vol 10 (3) ◽  
pp. 1121-1131 ◽  
Author(s):  
E.-G. Brunke ◽  
C. Labuschagne ◽  
R. Ebinghaus ◽  
H. H. Kock ◽  
F. Slemr
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Chemical Mechanism ◽  
Polar Regions ◽  
Gaseous Elemental Mercury ◽  
Transport Distance ◽  
Gaseous Mercury ◽  
Urban Emissions

Abstract. Gaseous mercury in the marine boundary layer has been measured with a 15 min temporal resolution at the Global Atmosphere Watch station Cape Point since March 2007. The most prominent features of the data until July 2008 are the frequent occurrences of pollution (PEs) and depletion events (DEs). Both types of events originate mostly within a short transport distance (up to about 100 km), which are embedded in air masses ranging from marine background to continental. The Hg/CO emission ratios observed during the PEs are within the range reported for biomass burning and industrial/urban emissions. The depletion of gaseous mercury during the DEs is in many cases almost complete and suggests an atmospheric residence time of elemental mercury as short as a few dozens of hours, which is in contrast to the commonly used estimate of approximately 1 year. The DEs observed at Cape Point are not accompanied by simultaneous depletion of ozone which distinguishes them from the halogen driven atmospheric mercury depletion events (AMDEs) observed in Polar Regions. Nonetheless, DEs similar to those observed at Cape Point have also been observed at other places in the marine boundary layer. Additional measurements of mercury speciation and of possible mercury oxidants are hence called for to reveal the chemical mechanism of the newly observed DEs and to assess its importance on larger scales.

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

2013 ◽  
Vol 10 (2) ◽  
pp. 102 ◽  
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 ◽  
Gaseous Elemental 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.

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