Abstract:

 While much research has been devoted to the subject of gaseous elemental mercury (GEM) and gaseous oxidized mercury (GOM) in the Arctic spring, during atmospheric mercury depletion events, few studies have examined the behavior of GOM in the High Arctic summer. GOM, once introduced into the ecosystem, can pose a threat to human and wildlife health, though there remain large uncertainties regarding the transformation, deposition, and assimilation of mercury into the ecosystem. Therefore, to further our understanding of the dynamics of gaseous oxidized mercury in the High Arctic during the late summer, we performed measurements of GEM and GOM along with meteorological parameters, atmospheric constituents, and air mass history during two summer campaigns in 2019 and 2020 at Villum Research Station (Villum) in Northeastern Greenland. Five events of enhanced GOM concentrations were identified and investigated in greater detail. The origin of these events was identified, through analysis of air mass back-trajectories, associated meteorological data, and other atmospheric constituents, to be the cold, dry free troposphere. These events were associated with low RH, limited precipitation, cold temperatures, and intense sunlight along the trajectory path. Events were positively correlated with ozone, aerosol particle number, and black carbon mass concentration, which were interpreted as an indication of tropospheric air masses. This work aims to provide a better understanding of the dynamics of GOM during the High Arctic summer.

 https://doi.org/10.5194/acp-2020-1287