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| Titel |
Long-term tropospheric trend of octafluorocyclobutane (c-C4F8 or PFC-318) |
| VerfasserIn |
D. E. Oram, F. S. Mani, J. C. Laube, M. J. Newland, C. E. Reeves, W. T. Sturges, S. A. Penkett, C. A. M. Brenninkmeijer, T. Röckmann, P. J. Fraser |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 1 ; Nr. 12, no. 1 (2012-01-05), S.261-269 |
| Datensatznummer |
250010433
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| Publikation (Nr.) |
 copernicus.org/acp-12-261-2012.pdf |
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| Zusammenfassung |
| Air samples collected at Cape Grim, Tasmania between 1978 and 2008 and
during a series of more recent aircraft sampling programmes have been
analysed to determine the atmospheric abundance and trend of
octafluorocyclobutane (c-C4F8 or PFC-318). c-C4F8 has an
atmospheric lifetime in excess of 3000 yr and a global warming potential
(GWP) of 10 300 (100 yr time horizon), making it one of the most potent
greenhouse gases detected in the atmosphere to date. The abundance of
c-C4F8 in the Southern Hemisphere has risen from 0.35 ppt in
1978 to 1.2 ppt in 2010, and is currently increasing at a rate of
around 0.03 ppt yr−1. It is the third most abundant perfluorocarbon (PFC) in the
present day atmosphere, behind CF4 (~75 ppt) and C2F6
(~4 ppt). Although a number of potential sources of c-C4F8
have been reported, including the electronics and semi-conductor industries,
there remains a large discrepancy in the atmospheric budget. Using a 2-D
global model to derive top-down global emissions based on the Cape Grim
measurements yields a recent (2007) emission rate of around 1.1 Gg yr−1
and a cumulative emission up to and including 2007 of 38.1 Gg. Emissions
reported on the EDGAR emissions database for the period 1986–2005 represent
less than 1% of the top-down emissions for the same period, which
suggests there is a large unaccounted for source of this compound. It is
also apparent that the magnitude of this source has varied considerably over
the past 30 yr, declining sharply in the late 1980s before increasing
again in the mid-1990s. |
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