Photochemical chlorine and bromine activation from artificial saline snow
The activation of reactive halogen species – particularly Cl 2 – from sea ice and snow surfaces is not well understood. In this study, we used a photochemical snow reactor coupled to a chemical ionization mass spectrometer to investigate the production of Br 2 , BrCl and Cl 2 from NaCl/NaBr-doped ar...
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ftcopernicus:oai:publications.copernicus.org:acp20161 2023-05-15T18:18:26+02:00 Photochemical chlorine and bromine activation from artificial saline snow Wren, S. N. Donaldson, D. J. Abbatt, J. P. D. 2018-01-15 application/pdf https://doi.org/10.5194/acp-13-9789-2013 https://www.atmos-chem-phys.net/13/9789/2013/ eng eng doi:10.5194/acp-13-9789-2013 https://www.atmos-chem-phys.net/13/9789/2013/ eISSN: 1680-7324 Text 2018 ftcopernicus https://doi.org/10.5194/acp-13-9789-2013 2019-12-24T09:55:01Z The activation of reactive halogen species – particularly Cl 2 – from sea ice and snow surfaces is not well understood. In this study, we used a photochemical snow reactor coupled to a chemical ionization mass spectrometer to investigate the production of Br 2 , BrCl and Cl 2 from NaCl/NaBr-doped artificial snow samples. At temperatures above the NaCl-water eutectic, illumination of samples (λ > 310 nm) in the presence of gas phase O 3 led to the accelerated release of Br 2 , BrCl and the release of Cl 2 in a process that was significantly enhanced by acidity, high surface area and additional gas phase Br 2 . Cl 2 production was only observed when both light and ozone were present. The total halogen release depended on [ozone] and pre-freezing [NaCl]. Our observations support a "halogen explosion" mechanism occurring within the snowpack, which is initiated by heterogeneous oxidation and propagated by Br 2 or BrCl photolysis and by recycling of HOBr and HOCl into the snowpack. Our study implicates this important role of active chemistry occurring within the interstitial air of aged (i.e. acidic) snow for halogen activation at polar sunrise. Text Sea ice Copernicus Publications: E-Journals Atmospheric Chemistry and Physics 13 19 9789 9800 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
The activation of reactive halogen species – particularly Cl 2 – from sea ice and snow surfaces is not well understood. In this study, we used a photochemical snow reactor coupled to a chemical ionization mass spectrometer to investigate the production of Br 2 , BrCl and Cl 2 from NaCl/NaBr-doped artificial snow samples. At temperatures above the NaCl-water eutectic, illumination of samples (λ > 310 nm) in the presence of gas phase O 3 led to the accelerated release of Br 2 , BrCl and the release of Cl 2 in a process that was significantly enhanced by acidity, high surface area and additional gas phase Br 2 . Cl 2 production was only observed when both light and ozone were present. The total halogen release depended on [ozone] and pre-freezing [NaCl]. Our observations support a "halogen explosion" mechanism occurring within the snowpack, which is initiated by heterogeneous oxidation and propagated by Br 2 or BrCl photolysis and by recycling of HOBr and HOCl into the snowpack. Our study implicates this important role of active chemistry occurring within the interstitial air of aged (i.e. acidic) snow for halogen activation at polar sunrise. |
format |
Text |
author |
Wren, S. N. Donaldson, D. J. Abbatt, J. P. D. |
spellingShingle |
Wren, S. N. Donaldson, D. J. Abbatt, J. P. D. Photochemical chlorine and bromine activation from artificial saline snow |
author_facet |
Wren, S. N. Donaldson, D. J. Abbatt, J. P. D. |
author_sort |
Wren, S. N. |
title |
Photochemical chlorine and bromine activation from artificial saline snow |
title_short |
Photochemical chlorine and bromine activation from artificial saline snow |
title_full |
Photochemical chlorine and bromine activation from artificial saline snow |
title_fullStr |
Photochemical chlorine and bromine activation from artificial saline snow |
title_full_unstemmed |
Photochemical chlorine and bromine activation from artificial saline snow |
title_sort |
photochemical chlorine and bromine activation from artificial saline snow |
publishDate |
2018 |
url |
https://doi.org/10.5194/acp-13-9789-2013 https://www.atmos-chem-phys.net/13/9789/2013/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-13-9789-2013 https://www.atmos-chem-phys.net/13/9789/2013/ |
op_doi |
https://doi.org/10.5194/acp-13-9789-2013 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
13 |
container_issue |
19 |
container_start_page |
9789 |
op_container_end_page |
9800 |
_version_ |
1766195008567771136 |