Current understanding of the driving mechanisms for spatiotemporal variations of atmospheric speciated mercury: a review

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dc.contributor.author
Mao, Huiting
Cheng, Irene
Zhang, Leiming
dc.date.accepted
2016-09-29
dc.date.accessioned
2023-10-06T19:10:50Z
dc.date.available
2023-10-06T19:10:50Z
dc.date.issued
2016-10-19
dc.date.submitted
2016-07-16
dc.description.abstract - en
Atmospheric mercury (Hg) is a global pollutant and thought to be the main source of mercury in oceanic and remote terrestrial systems, where it becomes methylated and bioavailable; hence, atmospheric mercury pollution has global consequences for both human and ecosystem health. Understanding of spatial and temporal variations of atmospheric speciated mercury can advance our knowledge of mercury cycling in various environments. This review summarized spatiotemporal variations of total gaseous mercury or gaseous elemental mercury (TGM/GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM) in various environments including oceans, continents, high elevation, the free troposphere, and low to high latitudes. In the marine boundary layer (MBL), the oxidation of GEM was generally thought to drive the diurnal and seasonal variations of TGM/GEM and GOM in most oceanic regions, leading to lower GEM and higher GOM from noon to afternoon and higher GEM during winter and higher GOM during spring–summer. At continental sites, the driving mechanisms of TGM/GEM diurnal patterns included surface and local emissions, boundary layer dynamics, GEM oxidation, and for high-elevation sites mountain–valley winds, while oxidation of GEM and entrainment of free tropospheric air appeared to control the diurnal patterns of GOM. No pronounced diurnal variation was found for Tekran measured PBM at MBL and continental sites. Seasonal variations in TGM/GEM at continental sites were attributed to increased winter combustion and summertime surface emissions, and monsoons in Asia, while those in GOM were controlled by GEM oxidation, free tropospheric transport, anthropogenic emissions, and wet deposition. Increased PBM at continental sites during winter was primarily due to local/regional coal and wood combustion emissions. Long-term TGM measurements from the MBL and continental sites indicated an overall declining trend. Limited measurements suggested TGM/GEM increasing from the Southern Hemisphere (SH) to the Northern Hemisphere (NH) due largely to the vast majority of mercury emissions in the NH, and the latitudinal gradient was insignificant in summer probably as a result of stronger meridional mixing. Aircraft measurements showed no significant vertical variation in GEM over the field campaign regions; however, depletion of GEM was observed in stratospherically influenced air masses. In examining the remaining questions and issues, recommendations for future research needs were provided, and among them is the most imminent need for GOM speciation measurements and fundamental understanding of multiphase redox kinetics.
dc.identifier.doi
https://doi.org/10.5194/acp-16-12897-2016
dc.identifier.issn
1680-7324
dc.identifier.uri
https://open-science.canada.ca/handle/123456789/1202
dc.language.iso
en
dc.publisher
European Geosciences Union
dc.rights - en
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.rights - fr
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.rights.openaccesslevel - en
Gold
dc.rights.openaccesslevel - fr
Or
dc.rights.uri - en
https://creativecommons.org/licenses/by/4.0/
dc.rights.uri - fr
https://creativecommons.org/licenses/by/4.0/deed.fr
dc.subject - en
Nature and environment
Science and technology
dc.subject - fr
Nature et environnement
Sciences et technologie
dc.subject.en - en
Nature and environment
Science and technology
dc.subject.fr - fr
Nature et environnement
Sciences et technologie
dc.title - en
Current understanding of the driving mechanisms for spatiotemporal variations of atmospheric speciated mercury: a review
dc.type - en
Article
dc.type - fr
Article
local.article.journalissue
20
local.article.journaltitle
Atmospheric Chemistry and Physics
local.article.journalvolume
16
local.pagination
14631-14656
local.peerreview - en
Yes
local.peerreview - fr
Oui
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