Variability in gaseous elemental mercury at Villum Research Station, Station Nord, in North Greenland from 1999 to 2017

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Skov, Henrik, Hjorth, J., Nordstrøm, Claus, Jensen, Bjarne, Christoffersen, Christel, Bech Poulsen, Maria, Baldtzer Liisberg, Jesper, Beddows, D.C.S., Dall'Osto, Manuel, Christensen, Jesper Heile
• Other Authors: Danish Environmental Protection Agency, European Commission, Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: European Geosciences Union 2020
• Subjects: Arctic; Greenland; Station Nord; North Greenland
• Online Access: http://hdl.handle.net/10261/227481; https://doi.org/10.5194/acp-20-13253-2020; https://doi.org/10.13039/501100000780; https://doi.org/10.13039/501100011033

Special issue Research results from the 14th International Conference on Mercury as a Global Pollutant (ICMGP 2019), MercOx project, and iGOSP and iCUPE projects of ERA-PLANET in support of the Minamata Convention on Mercury (ACP/AMT inter-journal SI).-- 13 pages, 9 figures, 1 table Mercury is ubiquitous in the atmosphere, and atmospheric transport is an important source for this element in the Arctic. Measurements of gaseous elemental mercury (GEM) have been carried out at Villum Research Station (Villum) at Station Nord, situated in northern Greenland. The measurements cover the period 1999–2017, with a gap in the data for the period 2003–2008 (for a total of 11 years). The measurements were compared with model results from the Danish Eulerian Hemispheric Model (DEHM) that describes the contribution from direct anthropogenic transport, marine emissions and general background concentration. The percentage of time spent over different surfaces was calculated by back-trajectory analysis, and the reaction kinetics were determined by a comparison with ozone. The GEM measurements were analysed for trends, both seasonal and annual. The only significant trends found were negative ones for the winter and autumn months. Comparison of the measurements to simulations using the Danish Eulerian Hemispheric Model (DEHM) indicated that direct transport of anthropogenic emissions of mercury accounts for between 14 % and 17 % of the measured mercury. Analysis of the kinetics of the observed atmospheric mercury depletion events (AMDEs) confirms the results of a previous study at Villum of the competing reactions of GEM and ozone with Br, which suggests that the lifetime of GEM is about a month. However, a GEM lifetime of 12 months gave the best agreement between the model and measurements. The chemical lifetime is shorter, and thus, the apparent lifetime appears to be the result of deposition followed by reduction and re-emission; for this reason, the term “relaxation time” is preferred to “lifetime” for GEM. The relaxation ...