Researchers at the University of East Anglia in Norwich said more than 74,000 metric tons of these gases, three new chlorofluorocarbons and one hydrochlorofluorocarbon, have been released into the atmosphere, Nature World News reported Monday.
Researchers said they examined air samples from polar firm snow -- which they characterized as a catalog of atmospheric conditions from a century ago -- and compared the older air samples with air collected from 1978 to 2012 in Tasmania.
"Our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are man-made," Johannes Laube from of the university's School of Environmental Sciences, said.
Researchers said the sources of the gases could include chemicals used in insecticide production.
Researchers found emission of the newly discovered CFCs and HCFC was higher than other gases in the same families, Nature World News said. However, they said, the increase hasn't reached the 1980s levels.
The study," Newly Detected Ozone-depleting Substances in the Atmosphere," was published in the latest edition of Nature Geoscience.