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| Titel |
Atmospheric histories and growth trends of C4F10, C5F12, C6F14, C7F16 and C8F18 |
| VerfasserIn |
D. J. Ivy, T. Arnold, C. M. Harth, L. P. Steele, J. Mühle, M. Rigby, P. K. Salameh, M. Leist, P. B. Krummel, P. J. Fraser, R. F. Weiss, R. G. Prinn |
| 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. 9 ; Nr. 12, no. 9 (2012-05-15), S.4313-4325 |
| Datensatznummer |
250011136
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| Publikation (Nr.) |
 copernicus.org/acp-12-4313-2012.pdf |
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| Zusammenfassung |
| Atmospheric observations and trends are presented for the high molecular
weight perfluorocarbons (PFCs): decafluorobutane (C4F10),
dodecafluoropentane (C5F12), tetradecafluorohexane (C6F14),
hexadecafluoroheptane (C7F16) and octadecafluorooctane
(C8F18). Their atmospheric histories are based on measurements of 36
Northern Hemisphere and 46 Southern Hemisphere archived air samples collected
between 1973 to 2011 using the Advanced Global Atmospheric Gases Experiment
(AGAGE) "Medusa" preconcentration gas chromatography-mass spectrometry
systems. A new calibration scale was prepared for each PFC, with estimated
accuracies of 6.8% for C4F10, 7.8% for C5F12, 4.0%
for C6F14, 6.6% for C7F16 and 7.9% for C8F18.
Based on our observations the 2011 globally averaged dry air mole fractions
of these heavy PFCs are: 0.17 parts-per-trillion (ppt, i.e., parts per
1012) for C4F10, 0.12 ppt for C5F12, 0.27 ppt for
C6F14, 0.12 ppt for C7F16 and 0.09 ppt for
C8F18. These atmospheric mole fractions combine to contribute to a
global average radiative forcing of 0.35 mW m−2, which is 6% of
the total anthropogenic PFC radiative forcing (Montzka and Reimann, 2011; Oram
et al., 2012). The growth rates of the heavy perfluorocarbons were largest in the late 1990s
peaking at 6.2 parts per quadrillion (ppq, i.e., parts per 1015) per
year (yr) for C4F10, at 5.0 ppq yr−1 for C5F12 and
16.6 ppq yr−1 for C6F14 and in the early 1990s for
C7F16 at 4.7 ppq yr−1 and in the mid 1990s for
C8F18 at 4.8 ppq yr−1. The 2011 globally averaged mean
atmospheric growth rates of these PFCs are subsequently lower at
2.2 ppq yr−1 for C4F10, 1.4 ppq yr−1 for C5F12,
5.0 ppq yr−1 for C6F14, 3.4 ppq yr−1 for C7F16
and 0.9 ppq yr−1 for C8F18. The more recent slowdown in the
growth rates suggests that emissions are declining as compared to the 1980s
and 1990s. |
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