February 28, 2007
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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 9, NUMBER 5, MAY 1996
OZONE DEPLETION: CFCS & THEIR REPLACEMENTS
"Toxicology of Chlorofluorocarbon Replacements," W. Dekant
(Dept. Toxicol., Univ. Würzburg, Versbacher Str. 9, 97078 Würzburg,
Ger.) Environ. Health Perspectives, 104(Suppl. 1), 75-83, Mar.
Describes an intensive study of the animal toxicology of HCFC-141b,
HFC-134a, HFC-125, HCFC-124, and HCFC-123. Determines that chronic toxicity is
unlikely to be important for humans exposed during production and application of
"Mineralization of Chlorofluorocarbons and Aromatization of
Saturated Fluorocarbons by a Convenient Thermal Process," J. Burdeniuc,
R.H. Crabtree (Dept. Chem., Yale Univ., New Haven CT 06520), Nature,
271(5247), 340-341, Jan. 19, 1996.
(See Research News, this Digest issue--May 1996.) Describes a
chemical reaction that enables the complete destruction of CFCs. The reaction
products are easily handled solids, including recyclable alkali metal halides.
Under milder conditions, the same reaction yields perfluoroarenes, which are
valuable chemical intermediates.
"Relative Effects and Halocarbon Global Warming Potentials of
Replacement Compounds for Chlorofluorocarbons," R. Imasu (Natl. Inst. for
Resources & Environ., Tsukuba, Ibaraki 305, Japan), A. Suga, T. Matsuno,
J. Meteor. Soc. Japan, 73(6), 1123-1136, Dec. 1995.
Instantaneous radiative forcing was calculated for 31 proposed CFC
replacements and, together with an estimate of atmospheric lifetime, was used to
determine global warming potentials. All are acceptable from the standpoint of
warming potential. However, the vertical structure of the radiative effects
shows that compounds whose absorption bands overlap with those of ozone cause
significant cooling in the stratosphere, even if the compound does not exist
there. This effect does not directly relate to warming potential, and must be
evaluated to provide a full assessment of the environmental effects of any
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