Methylchloroform: global distribution, seasonal cycles, and anthropogenic chlorine
It is evident that the global concentrations of methylchloroform (CH/sub 3/CCl/sub 3/) are increasing although at much lower rates than in the past. The ratio of concentrations in the two hemispheres has varied and is now declining, which reflects the constancy of the industrial emissions over the past 5 years. Observations show that the mid-latitude concentrations in both hemispheres are slightly lower during the summer than at other times, probably reflecting the greater removal of CH/sub 3/CCl/sub 3/ by OH radicals during summer. Calculations show that the lifetime of CH/sub 3/CCl/sub 3/ is about 6 (+/- 1.5) years, which is considerably shorter than many previous estimates. The shorter lifetime is partly due to a revision of the estimated absolute concentration of CH/sub 3/CCl/sub 3/ in the atmosphere, which was found to be about 20% less than estimated previously. The relatively short lifetime suggests that in the future CH/sub 3/CCl/sub 3/ will contribute <15% of the anthropogenic chlorine in the troposphere, which is an approximate measure of its relative contribution to the depletion of the stratospheric ozone layer.
- Research Organization:
- Oregon Graduate Center, Beaverton
- OSTI ID:
- 5861758
- Journal Information:
- Chemosphere; (United States), Journal Name: Chemosphere; (United States) Vol. 13:7; ISSN CHESB
- Country of Publication:
- United States
- Language:
- English
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Methylchloroform. Cycles of global emissions
Global atmospheric distribution and trend of methylchloroform (CH/sub 3/CCl/sub 3/)
Related Subjects
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
CHLOROFORM
ENVIRONMENTAL TRANSPORT
GLOBAL ASPECTS
HALOGENATED ALIPHATIC HYDROCARBONS
MASS TRANSFER
METHYLATION
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC SOLVENTS
SEASONAL VARIATIONS
SOLVENTS
VARIATIONS