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Stable Mercury Isotopes Revealing Photochemical Processes in the Marine Boundary Layer
Author(s) -
Qiu Yue,
Gai Pengxue,
Yue Fange,
Zhang Yuanyuan,
He Pengzhen,
Kang Hui,
Yu Xiawei,
Lam Paul K. S.,
Chen Jiubin,
Xie Zhouqing
Publication year - 2021
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2021jd034630
Subject(s) - mercury (programming language) , environmental chemistry , particulates , radical , chemistry , isotope , mass independent fractionation , adsorption , photochemistry , isotope fractionation , fractionation , organic chemistry , physics , quantum mechanics , computer science , programming language
The marine boundary layer (MBL) is an important transportation and reaction zone of atmospheric mercury on Earth. However, the transformation mechanisms of Hg in the MBL remain unclear. In this study, total suspended particle samples were collected in the MBL during two cruises, and the levels of particulate bound mercury (PBM) and mercury isotopes were analyzed. The results showed that (a) continental anthropogenic emissions have limited contribution to PBM in the MBL; (b) PBM likely experienced the oxidation of Hg 0 by Br radicals and subsequent adsorption of Hg 2+ on to particulate surfaces, as inferred from the significant negative δ 202 Hg; (c) the Δ 199 Hg/Δ 201 Hg ratio of ∼1.0 suggests that PBM underwent photoreduction, which was influenced by organic compounds, and the contribution of photoreduction to the extent of odd‐number mass‐independent fractionation in PBM in the MBL was more significant than that of oxidation triggered by Br atoms. This study provides insights into the photochemical processes influencing mercury in the MBL.