Evaluating CFC (chlorofluorocarbon) alternatives from the atmospheric viewpoint
Current understanding of atmospheric processes in the troposphere and stratosphere, in particular, stratospheric ozone-controlling photochemistry, allows evaluation of the effects on the stratosphere of chlorine-containing compounds envisioned as CFC (chlorofluorocarbon) replacements prior to their production and release. We employ a two-dimensional (latitude and altitude) computational representation of the troposphere and stratosphere which incorporates physical processes, e.g., species transport and radiative transfer, and homogeneous photochemical processes. Laboratory measurements of OH and O(/sup 1/D) reactivity and spectral parameters of the alternative HCFC (hydrochlorofluorocarbon) compounds were used as input. The model-derived ozone depletion potential (ODP) is a defined quantity relating the effect on ozone of emission of a species to the model-calculated effect of a standard compound, here CFC-11 (CFCl/sub 3/). Globally and annually averaged ozone depletion potentials vary from less than .02 to greater than 1.0 for various CFCs and HCFCs, primarily as a result of differences in calculated atmospheric lifetimes. Differences in stratospheric photochemistry among CFCs and HCFCs play a smaller but significant role. Zonally averaged ODPs for some compounds can range over a factor of three with latitude, however, as a result of differences in stratospheric lifetime and the altitude profile of Cl release in CFC or HCFC loss processes. 6 refs., 4 figs., 3 tabs.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5987974
- Report Number(s):
- UCRL-99927; CONF-890692-2; ON: DE89010238
- Resource Relation:
- Conference: 82. Air and Waste Management Association annual meeting and exhibition, Anaheim, CA, USA, 25 Jun 1989; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATMOSPHERIC CHEMISTRY
MODIFICATIONS
OZONE
ENVIRONMENTAL EFFECTS
GLOBAL ASPECTS
ORGANIC CHLORINE COMPOUNDS
PHOTOCHEMISTRY
STRATOSPHERE
TWO-DIMENSIONAL CALCULATIONS
CHEMISTRY
EARTH ATMOSPHERE
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)