Chloroform, carbon tetrachloride and methyl chloroform fluxes in southern California ecosystems

Rhew, RC, Miller BR, Weiss RF.  2008.  Chloroform, carbon tetrachloride and methyl chloroform fluxes in southern California ecosystems. Atmospheric Environment. 42:7135-7140.

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1,1,1-Trichloroethane, air, bromide, cape grim, china, chloride, coastal salt marshes, emissions, halocarbons, halomethanes, salt marsh, Shrubland, tasmania, Tetrachloromethane, Trichloromethane


Chloroform (CHCl3), carbon tetrachloride (CCl4), and methyl chloroform (CH3CCl3) are important carriers of chlorine to the stratosphere and account for an estimated 159 of the total organic chlorine in the troposphere, roughly equivalent to chlorine load due to methyl chloride (CH3Cl). The tropospheric burden of chlorine has declined since 1994, largely due to the restriction of CH3CCl3 and CCl4 use as specified by the Montreal Protocol. However, few field studies have been conducted on the terrestrial-atmosphere exchange of these chlorinated hydrocarbons, leading to uncertainties about the natural cycling of these trace gases. This work shows the results of 75 flux measurements conducted in a variety of southern California ecosystems, including coast sagebrush, chamise chaparral, creosote bush scrub, shoreline, and coastal salt marsh. We find no evidence of a significant soil sink in these ecosystems but rather a small net source of CHCl3 and possibly CCl4. (c) 2008 Elsevier Ltd. All rights reserved.