New ozone menace

IT WAS one environment problem we thought we had solved. But the ozone layer is under threat again. Four banned ozone-destroying chlorofluorocarbons (CFCs) have been detected in the atmosphere. And levels are rising fast, says Johannes Laube of the University of East Anglia, UK, whose team made the discovery. CFCs have been almost completely phased out under the 1987 Montreal Protocol. But Laube says a loophole allows one of the newly detected substances – CFC113a – to be used to make certain products such as insecticides. Total emissions of CFC-113a are still relatively small, but they are climbing fast, more than doubling between 2010 and mid-2012. The gas is used in the production of hydrofluorocarbons and some insecticides. It is unclear who is releasing it, and where. The ozone secretariat at the  UN Environment Programme in Nairobi, Kenya, received reports from governments that CFC-113a was being used to manufacture pesticides in 2003. “We simply don’t know if the emissions we have found in the atmosphere come from exempted emissions or if they are from illegal manufacture somewhere,” said Laube.