Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air
The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2), similar to effects...
Published in: | Atmospheric Chemistry and Physics |
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European Geosciences Union
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Online Access: | http://nora.nerc.ac.uk/id/eprint/509223/ https://nora.nerc.ac.uk/id/eprint/509223/1/acp-15-6867-2015.pdf |
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ftnerc:oai:nora.nerc.ac.uk:509223 2023-05-15T13:48:09+02:00 Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air Allin, S. J. Laube, J. C. Witrant, E. Kaiser, J. McKenna, E. Dennis, P. Mulvaney, R. Capron, E. Martinerie, P. Röckmann, T. Blunier, T. Schwander, J. Fraser, P. J. Langenfelds, R. L. Sturges, W. T. 2015-06-23 text http://nora.nerc.ac.uk/id/eprint/509223/ https://nora.nerc.ac.uk/id/eprint/509223/1/acp-15-6867-2015.pdf en eng European Geosciences Union https://nora.nerc.ac.uk/id/eprint/509223/1/acp-15-6867-2015.pdf Allin, S. J.; Laube, J. C.; Witrant, E.; Kaiser, J.; McKenna, E.; Dennis, P.; Mulvaney, R. orcid:0000-0002-5372-8148 Capron, E. orcid:0000-0003-0784-1884 Martinerie, P.; Röckmann, T.; Blunier, T.; Schwander, J.; Fraser, P. J.; Langenfelds, R. L.; Sturges, W. T. 2015 Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air. Atmospheric Chemistry and Physics, 15. 6867-6877. https://doi.org/10.5194/acp-15-6867-2015 <https://doi.org/10.5194/acp-15-6867-2015> cc_by CC-BY Publication - Article PeerReviewed 2015 ftnerc https://doi.org/10.5194/acp-15-6867-2015 2023-02-04T19:40:46Z The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2), similar to effects seen in nitrous oxide (N2O). Using air archives to obtain a long-term record of chlorine isotope ratios in CFCs could help to identify and quantify their sources and sinks. We analyse the three most abundant CFCs and show that CFC-11 (CCl3F) and CFC-113 (CClF2CCl2F) exhibit significant stratospheric chlorine isotope fractionation, in common with CFC-12. The apparent isotope fractionation (ϵapp) for mid- and high-latitude stratospheric samples are (−2.4 ± 0.5) and (−2.3 ± 0.4)‰ for CFC-11, (−12.2 ± 1.6) and (−6.8 ± 0.8)‰ for CFC-12 and (−3.5 ± 1.5) and (−3.3 ± 1.2)‰ for CFC-113, respectively. Assuming a constant source isotope composition, we estimate the expected trends in the tropospheric isotope signature of these gases due to their stratospheric 37Cl enrichment and stratosphere–troposphere exchange. We compare these model results to the long-term δ(37Cl) trends of all three CFCs, measured on background tropospheric samples from the Cape Grim air archive (Tasmania, 1978–2010) and tropospheric firn air samples from Greenland (NEEM site) and Antarctica (Fletcher Promontory site). Model trends agree with tropospheric measurements within analytical uncertainties. From 1970 to the present-day, we find no evidence for variations in chlorine isotope ratios associated with changes in CFC manufacturing processes. Our study increases the suite of trace gases amenable to direct isotope ratio measurements in small air volumes, using a single-detector gas chromatography-mass spectrometry system. Article in Journal/Newspaper Antarc* Antarctica Greenland Natural Environment Research Council: NERC Open Research Archive Greenland Grim ENVELOPE(-64.486,-64.486,-65.379,-65.379) Fletcher Promontory ENVELOPE(-80.000,-80.000,-78.416,-78.416) Atmospheric Chemistry and Physics 15 12 6867 6877 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2), similar to effects seen in nitrous oxide (N2O). Using air archives to obtain a long-term record of chlorine isotope ratios in CFCs could help to identify and quantify their sources and sinks. We analyse the three most abundant CFCs and show that CFC-11 (CCl3F) and CFC-113 (CClF2CCl2F) exhibit significant stratospheric chlorine isotope fractionation, in common with CFC-12. The apparent isotope fractionation (ϵapp) for mid- and high-latitude stratospheric samples are (−2.4 ± 0.5) and (−2.3 ± 0.4)‰ for CFC-11, (−12.2 ± 1.6) and (−6.8 ± 0.8)‰ for CFC-12 and (−3.5 ± 1.5) and (−3.3 ± 1.2)‰ for CFC-113, respectively. Assuming a constant source isotope composition, we estimate the expected trends in the tropospheric isotope signature of these gases due to their stratospheric 37Cl enrichment and stratosphere–troposphere exchange. We compare these model results to the long-term δ(37Cl) trends of all three CFCs, measured on background tropospheric samples from the Cape Grim air archive (Tasmania, 1978–2010) and tropospheric firn air samples from Greenland (NEEM site) and Antarctica (Fletcher Promontory site). Model trends agree with tropospheric measurements within analytical uncertainties. From 1970 to the present-day, we find no evidence for variations in chlorine isotope ratios associated with changes in CFC manufacturing processes. Our study increases the suite of trace gases amenable to direct isotope ratio measurements in small air volumes, using a single-detector gas chromatography-mass spectrometry system. |
format |
Article in Journal/Newspaper |
author |
Allin, S. J. Laube, J. C. Witrant, E. Kaiser, J. McKenna, E. Dennis, P. Mulvaney, R. Capron, E. Martinerie, P. Röckmann, T. Blunier, T. Schwander, J. Fraser, P. J. Langenfelds, R. L. Sturges, W. T. |
spellingShingle |
Allin, S. J. Laube, J. C. Witrant, E. Kaiser, J. McKenna, E. Dennis, P. Mulvaney, R. Capron, E. Martinerie, P. Röckmann, T. Blunier, T. Schwander, J. Fraser, P. J. Langenfelds, R. L. Sturges, W. T. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air |
author_facet |
Allin, S. J. Laube, J. C. Witrant, E. Kaiser, J. McKenna, E. Dennis, P. Mulvaney, R. Capron, E. Martinerie, P. Röckmann, T. Blunier, T. Schwander, J. Fraser, P. J. Langenfelds, R. L. Sturges, W. T. |
author_sort |
Allin, S. J. |
title |
Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air |
title_short |
Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air |
title_full |
Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air |
title_fullStr |
Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air |
title_full_unstemmed |
Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air |
title_sort |
chlorine isotope composition in chlorofluorocarbons cfc-11, cfc-12 and cfc-113 in firn, stratospheric and tropospheric air |
publisher |
European Geosciences Union |
publishDate |
2015 |
url |
http://nora.nerc.ac.uk/id/eprint/509223/ https://nora.nerc.ac.uk/id/eprint/509223/1/acp-15-6867-2015.pdf |
long_lat |
ENVELOPE(-64.486,-64.486,-65.379,-65.379) ENVELOPE(-80.000,-80.000,-78.416,-78.416) |
geographic |
Greenland Grim Fletcher Promontory |
geographic_facet |
Greenland Grim Fletcher Promontory |
genre |
Antarc* Antarctica Greenland |
genre_facet |
Antarc* Antarctica Greenland |
op_relation |
https://nora.nerc.ac.uk/id/eprint/509223/1/acp-15-6867-2015.pdf Allin, S. J.; Laube, J. C.; Witrant, E.; Kaiser, J.; McKenna, E.; Dennis, P.; Mulvaney, R. orcid:0000-0002-5372-8148 Capron, E. orcid:0000-0003-0784-1884 Martinerie, P.; Röckmann, T.; Blunier, T.; Schwander, J.; Fraser, P. J.; Langenfelds, R. L.; Sturges, W. T. 2015 Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air. Atmospheric Chemistry and Physics, 15. 6867-6877. https://doi.org/10.5194/acp-15-6867-2015 <https://doi.org/10.5194/acp-15-6867-2015> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/acp-15-6867-2015 |
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Atmospheric Chemistry and Physics |
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15 |
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12 |
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6867 |
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6877 |
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