Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols

Baker, Alex and Yodle, Chan (2021) Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols. Atmospheric Chemistry and Physics, 21 (17). 13067–13076. ISSN 1680-7324

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Abstract

The speciation of soluble iodine and major-ion composition were determined in size-fractionated aerosols collected during the AMT21 cruise between Avonmouth, UK, and Punta Arenas, Chile, in September-November 2011. The proportions of iodine species (iodide, iodate and soluble organic iodine (SOI)) varied markedly between size fractions and with the extent to which the samples were influenced by pollutants. In general, fine mode aerosols (< 1 μm) contained higher proportions of both iodide and SOI, while iodate was the dominant component of coarse (< 1 μm) aerosols. The highest proportions of iodate were observed in aerosols that contained (alkaline) unpolluted sea spray or mineral dust. Fine mode samples with high concentrations of acidic species (e.g. non-sea-salt sulfate) contained very little iodate and elevated proportions of iodide and SOI. These results are in agreement with modelling studies that indicate that iodate can be reduced under acidic conditions and that the resulting hypoiodous acid (HOI) can react with organic matter to produce SOI and iodide. Further work that investigates the link between iodine speciation and aerosol pH directly, as well as studies on the formation and decay of organo-iodine compounds under aerosol conditions, will be necessary before the importance of this chemistry in regulating aerosol iodine speciation can be confirmed.

Item Type: Article
Uncontrolled Keywords: atmospheric science ,/dk/atira/pure/subjectarea/asjc/1900/1902
Faculty \ School: Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 04 Sep 2021 00:06
Last Modified: 21 Sep 2021 01:33
URI: https://ueaeprints.uea.ac.uk/id/eprint/81306
DOI: 10.5194/acp-21-13067-2021

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