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More Ozone-Depleting Chlorofluorocarbons Detected In Atmosphere

Two compounds increasing in air and their origins should be investigated, researchers say

by Jyllian Kemsley
March 17, 2014 | A version of this story appeared in Volume 92, Issue 11

Once widely used as refrigerants, propellants, and solvents, chlorofluorocarbons (CFCs) released to the atmosphere cause the destruction of Earth’s protective ozone layer. Their prevalence has declined in the past two decades because of an international treaty to control their use. Nevertheless, researchers recently detected three CFCs and one hydrochlorofluorocarbon not previously observed in the atmosphere, reports an international group led by Johannes C. Laube of the University of East Anglia, in England (Nat. Geosci. 2014, DOI: 10.1038/ngeo2109). The compounds turned up in air and snow. Concentrations of two of the species—CFCl2CFCl2 and CF2ClCCl3—increased in the atmosphere from the 1970s to the mid-1990s, then began to slowly decrease, similar to previously tracked CFCs controlled by the treaty. Concentrations of two others, however—CF3CCl3 and CF3CH2Cl—continued to increase through 2012, when the study’s sampling ended. No data are available to pinpoint the origins of the still-increasing compounds, which are intermediates in refrigerant production; CF3CCl3 is also an insecticide feedstock. Although emissions of the compounds are far less than peak CFC emissions in the 1980s, their increases suggest that their sources should be investigated, Laube and colleagues say.


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