Ozone-Depleting Compound Persists, NASA Research Shows

Aug 25, 2014



NASA research shows Earth’s atmosphere contains an unexpectedly large amount of an ozone-depleting compound from an unknown source decades after the compound was banned worldwide.

Carbon tetrachloride (CCl4), which was once used in applications such as dry cleaning and as a fire-extinguishing agent, was regulated in 1987 under the Montreal Protocol along with other chlorofluorocarbons that destroy ozone and contribute to the ozone hole over Antarctica. Parties to the Montreal Protocol reported zero new CCl4 emissions between 2007-2012.

However, the new research shows worldwide emissions of CCl4 average 39 kilotons per year, approximately 30 percent of peak emissions prior to the international treaty going into effect.

“We are not supposed to be seeing this at all,” said Qing Liang, an atmospheric scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study. “It is now apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or unknown CCl4 sources.”

5 comments on “Ozone-Depleting Compound Persists, NASA Research Shows

  • Lets hope we can find how these particles are still getting in to the atmosphere, it’s a threat to the survival all species on this planet.

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  • My thoughts exactly, although it could also be explained by careless or even reckless damage done to the sealed refrigerant systems of countless old fridges/freezers…In the UK thousands of old fridges and freezers are simply left outside peoples houses or dumped illegally because scrap yards won’t take them and the radiators on their back are easily damaged by careless handling, plus they are a magnet for vandals and the CFC ignorant. The problem has been caused by the British governments insistence that consumers have to pay someone to dispose of their old fridges and freezers…Which most are loathe to do of course. Now multiply that problem globally and its obvious where those thousands of tonnes of CFC’s could be coming from.

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  • John Aug 27, 2014 at 6:42 am

    CCl4 has nothing to do with CFCs or old fridges.

    That does not seem to be correct!

    Carbon tetrachloride is most often found in the air as a colorless gas. It is not flammable and does not dissolve in water very easily. It was used in the production of refrigeration fluid and propellants for aerosol cans, as a pesticide, as a cleaning fluid and degreasing agent, in fire extinguishers, and in spot removers. Because of its harmful effects, these uses are now banned and it is only used in some industrial applications.

    My guess is volcanoes. They are known sources of chlorine emission.

    *** Carbon tetrachloride is a manufactured chemical that does not occur naturally.**

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