Widespread detection of chlorine oxyacids in the Arctic atmosphere

• Published in: Nature Communications
• Main Authors: Tham, Yee Jun, Sarnela, Nina, Iyer, Siddharth, Li, Qinyi, Angot, Hélène, Quéléver, Lauriane L. J., Beck, Ivo, Laurila, Tiia, Beck, Lisa J., Boyer, Matthew, Carmona-García, Javier, Borrego-Sánchez, Ana, Roca-Sanjuán, Daniel, Peräkylä, Otso, Thakur, Roseline C., He, Xu-Cheng, Zha, Qiaozhi, Howard, Dean, Blomquist, Byron, Archer, Stephen D., Bariteau, Ludovic, Posman, Kevin, Hueber, Jacques, Helmig, Detlev, Jacobi, Hans-Werner, Junninen, Heikki, Kulmala, Markku, Mahajan, Anoop S., Massling, Andreas, Skov, Henrik, Sipilä, Mikko, Francisco, Joseph S., Schmale, Julia, Jokinen, Tuija, Saiz-Lopez, A.
• Other Authors: National Natural Science Foundation of China, European Commission, Academy of Finland, University of Helsinki, National Science Foundation (US), Swiss National Science Foundation, Swiss Polar Institute, Ferring Pharmaceuticals, Fundación "la Caixa", Ministerio de Ciencia e Innovación (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2023
• Subjects: Arctic; Arctic Ocean; Greenland; Ny-Ålesund; Ny Ålesund
• Online Access: http://hdl.handle.net/10261/332044; https://doi.org/10.1038/s41467-023-37387-y; https://api.elsevier.com/content/abstract/scopus_id/85151316278

14 pags., 3 figs. Chlorine radicals are strong atmospheric oxidants known to play an important role in the depletion of surface ozone and the degradation of methane in the Arctic troposphere. Initial oxidation processes of chlorine produce chlorine oxides, and it has been speculated that the final oxidation steps lead to the formation of chloric (HClO3) and perchloric (HClO4) acids, although these two species have not been detected in the atmosphere. Here, we present atmospheric observations of gas-phase HClO3 and HClO4. Significant levels of HClO3 were observed during springtime at Greenland (Villum Research Station), Ny-Ålesund research station and over the central Arctic Ocean, on-board research vessel Polarstern during the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) campaign, with estimated concentrations up to 7 × 106 molecule cm-3. The increase in HClO3, concomitantly with that in HClO4, was linked to the increase in bromine levels. These observations indicated that bromine chemistry enhances the formation of OClO, which is subsequently oxidized into HClO3 and HClO4 by hydroxyl radicals. HClO3 and HClO4 are not photoactive and therefore their loss through heterogeneous uptake on aerosol and snow surfaces can function as a previously missing atmospheric sink for reactive chlorine, thereby reducing the chlorine-driven oxidation capacity in the Arctic boundary layer. Our study reveals additional chlorine species in the atmosphere, providing further insights into atmospheric chlorine cycling in the polar environment. This study received funding from the National Natural Science Foundation of China (42175118), European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation Program (Project ERC-2016-COG726349 CLIMAHAL, ERC-StG GASPARCON - grant agreement no. 714621, the EMME-CARE project – grant agreement no. 856612, and grant no. 101002728, ATM-GTP Contract No. 742206), Climate Relevant interactions and feedbacks: the key ...