Scientists have found four new man-made harmful gases that affect the protective ozone layer above the earth's surface. Three types of CFCs (chlorofluorocarbon) and one HCFC (hydrochlorofluorocarbon) gases are being released, despite the 1987 Montreal Protocol ban on releasing harmful gases into the Earth atmosphere.
Experts found tiny traces of the new industrial effluent gases that were probably used in making refrigerants or pesticides. These gases were earlier found in Greenland's ice and in Tasmania's air samples.
The ozone layer is a protective layer that shields the Earth from harmful ultraviolet rays, that can be the major cause for skin cancer, eye cataract in humans.
"The concentrations are not yet a threat to the ozone layer," Reuters quoted Johannes Laube, University of East Anglia and lead author of the study.
It is likely that the new gases are powerful greenhouse gases, although present in small amounts and that CFCs can trap the atmospheric heat thousand times more than carbon dioxide.
Scientists have estimated that in total, over 74,000 metric tons of these four gases had been released into environment. According to a study in Nature Geoscience journal, none of these were found in the atmosphere before 1960s, which suggest that these are man-made gases.
However, it was not certain whether emission of the new gases into the atmosphere were against the law as the Montreal Protocol carried some exemptions. "We hope to tighten the loopholes," Laube said.
Ozone layer was first detected with a hole in 1980s over Antarctica. However, scientists are hoping that bans on harmful chemicals such as use of foams, hairsprays and refrigerants will be implemented in about 50 years from now.
Gases detected in Greenland indicated that they were produced in the northern hemisphere and then carried away to the south. Collecting air samples from all around the world may help in detecting the source, researchers plan.
"While these newly discovered gases can, in theory, cause some damage to the ozone layer, their combined abundance is over 500 times smaller than that of the main ozone-destroying compounds in the 1990s," said Martyn Chipperfield, Professor of Atmospheric Chemistry, University of Leeds.
"These new observations do not present concern at the moment, although the fact that these gases are in the atmosphere and some are increasing needs investigation," he said.
(Edited by Anu James)
