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Atmospheric fate of CF sub 3 Br, CF sub 2 Br sub 2 , CF sub 2 ClBr, and CF sub 2 BrCF sub 2 Br

Journal Article · · Journal of Geophysical Research; (United States)
DOI:https://doi.org/10.1029/90JD02735· OSTI ID:5331291
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  1. National Oceanic and Atmospheric Administration, Boulder, CO (USA) Univ. of Colorado, Boulder (USA)

The temperature dependent UV absorption cross sections of the haloalkanes CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}Br{sub 2}, and CF{sub 2}BrCF{sub 2} are reported. The UV absorption cross sections were measured over the temperature range 210 to 296 K and the wavelength range 190 to 320 nm. Upper limits of the rate coefficients for the reactions of OH with CF{sub 3}Br, CF{sub 2}Br{sub 2}, CF{sub 2}ClBr, and CF{sub 2}BrCF{sub 2}Br were also determined using both pulsed photolysis and flow tube techniques. The rate coefficients at 296 K were found to be <1.2 {times} 10{sup {minus}16}, <1.5 {times} 10{sup {minus}16}, <5.0 {times} 10{sup {minus}16}, and <1.5 {times} 10{sup {minus}16} cm{sup 3} molec{sup {minus}1} s{sup {minus}1} for CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}BrCF{sub 2}Br, respectively. The UV absorption cross-section data and OH reaction rate coefficients of these species were combined with a one-dimensional model to yield atmospheric lifetimes of 65, 16, 3.2, and <20 years for CF{sub 3}Br, CF{sub 2}ClBr, CF{sub 2}Br{sub 2}, and CF{sub 2}BrCF{sub 2}Br, respectively.

OSTI ID:
5331291
Journal Information:
Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:D3; ISSN JGREA; ISSN 0148-0227
Country of Publication:
United States
Language:
English