[Reproduced from BBC NEWS - Online]
The evidence quickly pointed to CFC gases, which were invented in the 1920s, and were widely used in refrigeration and as aerosol propellants in products like hairsprays and deodorants.
Now, researchers from the University of East Anglia have discovered evidence of four new gases that can destroy ozone and are getting into the atmosphere from as yet unidentified sources.
Three of the gases are CFCs and one is a hydrochlorofluorocarbon (HCFC), which can also damage ozone. "Our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are man-made," said lead researcher Dr Johannes Laube.
The researchers also looked at modern air samples, collected at remote Cape Grim in Tasmania.
They estimate that about 74,000 tonnes of these gases have been released into the atmosphere. Two of the gases are accumulating at significant rates.
"The identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer," said Dr Laube.
"Of the four species identified, CFC-113a seems the most worrying as there is a very small but growing emission source somewhere, maybe from agricultural insecticides. We should find it and take it out of production."
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