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Atmospheric Fluoroform (CHF3, HFC-23) at Cape Grim, Tasmania
D. E. Oram,1 W. T. Sturges,1 S. A. Penkett,1 A. McCulloch,2 and P. J.
1School of Environmental Sciences,
University of East Anglia,
Norwich NR4 7TJ,
2ICI Chemicals & Polymers Ltd.,
Safety and Environment Department, Runcorn,
Cheshire, WA7 4QD,
3CRC for Southern Hemisphere Meteorology,
Division of Atmospheric Research,
Commonwealth Scientific and Industrial Research Organization,
Private Bag No. 1, Aspendale,
Victoria 3195, Australia
Period of Record
The sampling and analytical methods are described more fully in Oram et al. (1998). In summary, air samples were taken from the archive of Cape Grim, Tasmania (41oS, 145oE) air samples collected from 1978 through 1995. Comparisons of CFC-11, CFC-12, CFC-113, CH3CCl3, and CH4 data between archive samples and corresponding in-situ samples for the same dates confirm that the archive samples are both representative and stable over time. Samples were analyzed by gas chromatography-mass spectrometry (GC-MS), using a KCl-passivated alumina PLOT column. Fluoroform was monitored on mass 69 (CF3+). The analytical precision (one standard deviation of the mean) for two or three replicate analyses was typically ± 1% of the mean measured value. The overall uncertainty of the observed data is ± 10%, taking into account uncertainties in the preparation of the primary standards, the purity of the fluoroform used to make the primary standards, as well as the analytical precision.
The measured concentration of fluoroform at Cape Grim has increased from about 2 pptv in early 1978 to about 11 pptv by late 1995. The current growth rate is 0.55 pptv per year over the period 1990-1995, or about 5% per year relative to the late 1995 value.
- Oram, D.E., W.T. Sturges, S.A. Penkett, A. McCulloch, and P.J. Fraser. 1998. Growth of fluoroform (CHF3, HFC-23) in the background atmosphere. Geophysical Research Letters 25:35-38.
CITE AS: Oram, D.E., W.T. Sturges, S.A. Penkett, A. McCulloch, and P.J. Fraser. 2000. Atmospheric Fluoroform (CHF3, HFC-23) at Cape Grim, Tasmania. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.