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14 What happens to the Fluorine from the CFC's?




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This article is from the Ozone Depletion: Stratospheric Chlorine and Bromine FAQ, by Robert Parson rparson@spot.colorado.edu with numerous contributions by others.

14 What happens to the Fluorine from the CFC's?

Most of it ends up as Hydrogen Fluoride, HF. The total amount of HF
in the stratosphere increased by a factor of 3-4 between 1978 and
1989 [Zander et al., 1990] [Rinsland et al.]; the relative increase
is larger for HF than for HCl (a factor of 2.2 over the same period)
because the natural source, and hence the baseline concentration,
is much smaller. For the same reason, the _ratio_ of HF to HCl has
increased, from 0.14 in 1977 to 0.23 in 1990. As discussed above, the
decomposition of CFC's in the stratosphere produces reaction
intermediates such as COF2 and COFCl which have been detected in the
stratosphere. COF2 in particular is relatively stable and makes a
significant contribution to the total fluorine; the total amount
of COF2 in the stratosphere increased by 60% between 1985 and 1992
[Zander et al. 1994] The total Fluorine budget,
as a function of altitude, adds up in much the same way as the
chlorine budget. [Zander et al. 1992, 1994] [Luo et al.]

The most comprehensive measurements of stratospheric HF are those made
by the Halogen Occultation Experiment (HALOE) on the UARS satellite
[Luo et al.] [Russell et al. 1996] Information about HALOE is available
on the World-Wide-Web at http://haloedata.larc.nasa.gov/home.html .

 

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