Photoreduction of gaseous oxidized mercury changes global atmospheric mercury speciation, transport and deposition

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Abstract

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.

Metadata

Item Type:	Article
Authors/Creators:	Saiz-Lopez, A Sitkiewicz, SP Roca-Sanjuan, D Oliva-Enrich, JM Davalos, JZ Notario, R Jiskra, M Xu, Y Wang, F Thackray, CP Sunderland, EM Jacob, DJ Travnikov, O Cuevas, CA Acuna, AU Rivero, D Plane, JMC https://orcid.org/0000-0003-3648-6893 Kinnison, DE Sonke, JE
Copyright, Publisher and Additional Information:	© The Author(s) 2018. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Dates:	Accepted: 11 October 2018 Published (online): 15 November 2018 Published: 15 November 2018
Institution:	The University of Leeds
Academic Units:	The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds)
Depositing User:	Symplectic Publications
Date Deposited:	24 Oct 2018 12:51
Last Modified:	25 Jun 2023 21:33
Status:	Published
Publisher:	Springer Nature
Identification Number:	10.1038/s41467-018-07075-3
Open Archives Initiative ID (OAI ID):	oai:eprints.whiterose.ac.uk:137528

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Photoreduction of gaseous oxidized mercury changes global atmospheric mercury speciation, transport and deposition. (deposited 24 Oct 2018 12:51) [Currently Displayed]
- Author Correction: Photoreduction of gaseous oxidized mercury changes global atmospheric mercury speciation, transport and deposition. (deposited 21 Feb 2022 15:09)

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