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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-497
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
02 Jun 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
A growing threat to the ozone layer from short-lived anthropogenic chlorocarbons
David E. Oram1,2, Matthew J. Ashfold3, Johannes C. Laube2, Lauren J. Gooch2, Stephen Humphrey2, William T. Sturges2, Emma Leedham-Elvidge2,8, Grant L. Forster1,2, Neil R. P. Harris4, Mohammed Iqbal Mead4,5, Azizan Abu Samah5, Siew Moi Phang5, Ou-Yang Chang-Feng6, Neng-Huei Lin6, Jia-Lin Wang7, Angela K. Baker8, Carl A. M. Brenninkmeijer8, and David Sherry9 1National Centre for Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
2Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK
3School of Biosciences, University of Nottingham Malaysia Campus, 43500 Semenyih, Malaysia
4Centre for Atmospheric Informatics and Emissions Technology, School of Energy, Environment and Agrifood/Environmental Technology, Cranfield University, UK
5Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur, Malaysia
6Department of Atmospheric Sciences, National Central University, Chungli, Taiwan
7Department of Chemistry, National Central University, Chungli, Taiwan
8Max Planck Institute for Chemistry, Air Chemistry Division, Mainz, Germany
9Nolan Sherry & Associates, Kingston upon Thames, UK
Abstract. Large and effective reductions in emissions of long-lived ozone-depleting substance (ODS) are being achieved through the Montreal Protocol, the effectiveness of which can be seen in the declining atmospheric abundances of many ODS. An important remaining uncertainty concerns the role of very short lived substances (VSLS) which, owing to their relatively short atmospheric lifetimes (less than 6 months), are not regulated under the Montreal Protocol. Recent studies have found an unexplained increase in the global tropospheric abundance of one VSLS, dichloromethane (CH2Cl2), which has increased by around 60 % over the past decade. Here we report dramatic enhancements of several chlorine-containing VSLS, including CH2Cl2 and CH2ClCH2Cl (1,2-dichloroethane), observed in surface and upper tropospheric air in East and South East Asia. Surface observations were an order of magnitude higher than previously reported in the marine boundary layer, whilst upper tropospheric data were up to 3 times higher than expected. In addition we provide further evidence of an atmospheric transport mechanism whereby substantial amounts of industrial pollution from East Asia, including these chlorinated VSLS, can rapidly, and regularly, be transported to tropical regions of the western Pacific and subsequently uplifted to the tropical upper troposphere. This latter region is a major provider for air entering the stratosphere and so this mechanism, in conjunction with increasing emissions of Cl-VSLS from East Asia, could potentially slow the expected recovery of stratospheric ozone.

Citation: Oram, D. E., Ashfold, M. J., Laube, J. C., Gooch, L. J., Humphrey, S., Sturges, W. T., Leedham-Elvidge, E., Forster, G. L., Harris, N. R. P., Mead, M. I., Abu Samah, A., Phang, S. M., Chang-Feng, O.-Y., Lin, N.-H., Wang, J.-L., Baker, A. K., Brenninkmeijer, C. A. M., and Sherry, D.: A growing threat to the ozone layer from short-lived anthropogenic chlorocarbons, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-497, in review, 2017.
David E. Oram et al.
David E. Oram et al.
David E. Oram et al.

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