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., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5987974
- Report Number(s):
- UCRL-99927; CONF-890692-2; ON: DE89010238
- Country of Publication:
- United States
- Language:
- English
Similar Records
Aspects of CFC relative ozone destruction efficiencies determined in the LLNL 2-D model
CFCs (chlorofluorocarbons) and electric utilities: Making the transition to a safer world
Related Subjects
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ATMOSPHERIC CHEMISTRY
CHEMISTRY
EARTH ATMOSPHERE
ENVIRONMENTAL EFFECTS
GLOBAL ASPECTS
MODIFICATIONS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OZONE
PHOTOCHEMISTRY
STRATOSPHERE
TWO-DIMENSIONAL CALCULATIONS