Sponsor
Major financial support for this work was provided by the Chemical Manufacturers' Association (CEFIC) via the Chlorine Chemistry Council and by the European Chemical Industry Council Euro Chlor. Additional support was provided by the resources of Andarz Co.
Published In
Journal of Geophysical Research
Document Type
Article
Publication Date
4-20-1999
Subjects
Chlorine compounds -- Environmental aspects, Environmental chemistry, Chloroform -- Environmental aspects, Greenhouse gases -- Environmental aspects
Abstract
Although there are many chlorine-containing trace gases in the atmosphere, only those with atmospheric lifetimes of 2 years or fewer appear to have significant natural sources. The most abundant of these gases are methyl chloride, chloroform, dichloromethane, perchloroethylene, and trichloroethylene. Methyl chloride represents about 540 parts per trillion by volume (pptv) Cl, while the others together amount to about 120 pptv Cl. For methyl chloride and chloroform, both oceanic and land-based natural emissions have been identified. For the other gases, there is evidence of oceanic emissions, but the roles of the soils and land are not known and have not been studied. The global annual emission rates from the oceans are estimated to be 460 Gg Cl/yr for CH₃Cl, 320 Gg Cl/yr for CHCl₃, 160 Gg Cl/yr for CH2Cl2, and about 20 Gg Cl/yr for each of C₂HCl₃, and C₂Cl₄. Land-based emissions are estimated to be 100 Gg Cl/yr for CH3Cl and 200 Gg Cl/yr for CHCl3. These results suggest that the oceans account for about 12% of the global annual emissions of methyl chloride, although until now oceans were thought to be the major source. For chloroform, natural emissions from the oceans and lands appear to be the major sources. For further research, the complete database compiled for this work is available from the archive, which includes a monthly emissions inventory on a 1degtimes1deg latitude-longitude grid for oceanic emissions of methyl chloride.
DOI
10.1029/1998JD100079
Persistent Identifier
http://archives.pdx.edu/ds/psu/7600
Citation Details
Khalil, M. A. K., R. M. Moore, D. B. Harper, J. M. Lobert, D. J. Erickson, V. Koropalov, W. T. Sturges, and W. C. Keene (1999), Natural emissions of chlorine-containing gases: Reactive Chlorine Emissions Inventory, J. Geophys. Res., 104(D7), 8333–8346
Description
Copyright 1999 by the American Geophysical Union. Originally published in the Journal of Geophysical Research and can be found online at: https://doi.org/10.1029/1998JD100079