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

<p>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...

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Main Authors: A. R. Baker, C. Yodle
Format: Article
Language:English
Published: Copernicus Publications 2021-09-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/21/13067/2021/acp-21-13067-2021.pdf
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author A. R. Baker
C. Yodle
C. Yodle
author_facet A. R. Baker
C. Yodle
C. Yodle
author_sort A. R. Baker
collection DOAJ
description <p>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 (<span class="inline-formula"><i>&lt;</i></span> 1 <span class="inline-formula">µ</span>m) contained higher proportions of both iodide and SOI, while iodate was the dominant component of coarse (<span class="inline-formula"><i>&lt;</i></span> 1 <span class="inline-formula">µ</span>m) 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.</p>
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spelling doaj.art-f150ebe8c8cd48459ffbb0270f3639632022-12-21T18:32:59ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242021-09-0121130671307610.5194/acp-21-13067-2021Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosolsA. R. Baker0C. Yodle1C. Yodle2Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UKCentre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UKnow at: Department of Environmental Science, Faculty of Science and Technology, Chiang Mai Rajabhat University, Chiang Mai, 50300, Thailand<p>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 (<span class="inline-formula"><i>&lt;</i></span> 1 <span class="inline-formula">µ</span>m) contained higher proportions of both iodide and SOI, while iodate was the dominant component of coarse (<span class="inline-formula"><i>&lt;</i></span> 1 <span class="inline-formula">µ</span>m) 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.</p>https://acp.copernicus.org/articles/21/13067/2021/acp-21-13067-2021.pdf
spellingShingle A. R. Baker
C. Yodle
C. Yodle
Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols
Atmospheric Chemistry and Physics
title Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols
title_full Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols
title_fullStr Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols
title_full_unstemmed Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols
title_short Measurement report: Indirect evidence for the controlling influence of acidity on the speciation of iodine in Atlantic aerosols
title_sort measurement report indirect evidence for the controlling influence of acidity on the speciation of iodine in atlantic aerosols
url https://acp.copernicus.org/articles/21/13067/2021/acp-21-13067-2021.pdf
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