TY - JOUR
T1 - Photoreduction of gaseous oxidized mercury changes global atmospheric mercury speciation, transport and deposition
AU - Saiz-Lopez, Alfonso
AU - Sitkiewicz, Sebastian P.
AU - Roca-Sanjuán, Daniel
AU - Oliva-Enrich, Josep M.
AU - Dávalos, Juan Z.
AU - Notario, Rafael
AU - Jiskra, Martin
AU - Xu, Yang
AU - Wang, Feiyue
AU - Thackray, Colin P.
AU - Sunderland, Elsie M.
AU - Jacob, Daniel J.
AU - Travnikov, Oleg
AU - Cuevas, Carlos A.
AU - Acuña, A. Ulises
AU - Rivero, Daniel
AU - Plane, John M.C.
AU - Kinnison, Douglas E.
AU - Sonke, Jeroen E.
N1 - Publisher Copyright:
© 2018, The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Anthropogenic mercury (Hg(0)) emissions oxidize to gaseous Hg(II) compounds, before deposition to Earth surface ecosystems. Atmospheric reduction of Hg(II) competes with deposition, thereby modifying the magnitude and pattern of Hg deposition. Global Hg models have postulated that Hg(II) reduction in the atmosphere occurs through aqueous-phase photoreduction that may take place in clouds. Here we report that experimental rainfall Hg(II) photoreduction rates are much slower than modelled rates. We compute absorption cross sections of Hg(II) compounds and show that fast gas-phase Hg(II) photolysis can dominate atmospheric mercury reduction and lead to a substantial increase in the modelled, global atmospheric Hg lifetime by a factor two. Models with Hg(II) photolysis show enhanced Hg(0) deposition to land, which may prolong recovery of aquatic ecosystems long after Hg emissions are lowered, due to the longer residence time of Hg in soils compared with the ocean. Fast Hg(II) photolysis substantially changes atmospheric Hg dynamics and requires further assessment at regional and local scales.
AB - Anthropogenic mercury (Hg(0)) emissions oxidize to gaseous Hg(II) compounds, before deposition to Earth surface ecosystems. Atmospheric reduction of Hg(II) competes with deposition, thereby modifying the magnitude and pattern of Hg deposition. Global Hg models have postulated that Hg(II) reduction in the atmosphere occurs through aqueous-phase photoreduction that may take place in clouds. Here we report that experimental rainfall Hg(II) photoreduction rates are much slower than modelled rates. We compute absorption cross sections of Hg(II) compounds and show that fast gas-phase Hg(II) photolysis can dominate atmospheric mercury reduction and lead to a substantial increase in the modelled, global atmospheric Hg lifetime by a factor two. Models with Hg(II) photolysis show enhanced Hg(0) deposition to land, which may prolong recovery of aquatic ecosystems long after Hg emissions are lowered, due to the longer residence time of Hg in soils compared with the ocean. Fast Hg(II) photolysis substantially changes atmospheric Hg dynamics and requires further assessment at regional and local scales.
UR - https://www.scopus.com/pages/publications/85056665149
U2 - 10.1038/s41467-018-07075-3
DO - 10.1038/s41467-018-07075-3
M3 - Article
C2 - 30442890
AN - SCOPUS:85056665149
SN - 2041-1723
VL - 9
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 4796
ER -