Atmospheric mercury speciation dynamics at the high-altitude Pic du Midi Observatory, southern France - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Atmospheric Chemistry and Physics Année : 2016

Atmospheric mercury speciation dynamics at the high-altitude Pic du Midi Observatory, southern France

Résumé

Continuous measurements of atmospheric gaseous elemental mercury (GEM), 16 particulate bound mercury (PBM) and gaseous oxidized mercury (GOM) at the high-altitude Pic 17 du Midi Observatory (PDM, 2877 m a.s.l) in southern France were made from Nov 2011 to Nov 18 2012. The mean GEM, PBM and GOM concentrations were 1.86 ng m-3, 14 pg m-3 and 27 pg m-3, 19 respectively and we observed 44 high PBM (up to 98 pg m-3) and 61 high GOM (up to 295 pg m-3) 20 events. The high PBM events occurred mainly in cold seasons (winter and spring) whereas high 21 GOM events were mainly observed in the warm seasons (summer and autumn). In cold seasons 22 the maximum air mass residence times (ARTs) associated with high PBM events were observed in 23 the upper troposphere over North America. The ratios of high PBM ARTs to total ARTs over North 24 America, Europe, the Arctic region and Atlantic Ocean were all elevated in the cold season 25 compared to the warm season, indicating that the middle and upper free troposphere of the 26 Northern Hemisphere may be more enriched in PBM in cold seasons. PBM concentrations and 27 PBM/GOM ratios during the high PBM events were significantly anti-correlated with atmospheric 28 aerosol concentrations, air temperature and solar radiation, suggesting in situ formation of PBM in 29 the middle and upper troposphere. We identified two distinct types of high GOM events with the 30 GOM concentrations positively and negatively correlated with atmospheric ozone concentrations, 31 respectively. High GOM events positively correlated with ozone were mainly related to air masses 32 from the upper troposphere over the Arctic region and middle troposphere over the temperate 33 North Atlantic Ocean, whereas high GOM events anti-correlated with ozone were mainly related 34 to air masses from the lower free troposphere over the subtropical North Atlantic Ocean. The 35 ARTs analysis demonstrates that the lower and middle free troposphere over the North Atlantic 36 Ocean was the largest source region of atmospheric GOM at PDM Observatory. The ratios of high 37 GOM ARTs to total ARTs over the subtropical North Atlantic Ocean in summer were significantly 38 higher than that over the temperate and sub-arctic North Atlantic Ocean as well as that over the 39 North Atlantic Ocean in other seasons, indicating abundant in situ oxidation of GEM to GOM in 40 the lower free troposphere over the subtropical North Atlantic Ocean in summer.
Fichier principal
Vignette du fichier
acp-2015-842.pdf (6.81 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-02163095 , version 1 (22-01-2020)

Licence

Paternité

Identifiants

Citer

X. Fu, N. Marusczak, Lars-Eric Heimbürger-Boavida, B. Sauvage, F. Gheusi, et al.. Atmospheric mercury speciation dynamics at the high-altitude Pic du Midi Observatory, southern France. Atmospheric Chemistry and Physics, 2016, pp.1-35. ⟨10.5194/acp-2015-842⟩. ⟨hal-02163095⟩
72 Consultations
33 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More