Scientists Find Four New Ozone-Depleting Gases

Researchers have found four new man-made gases that are depleting the ozone blanket.

University of East Anglia researchers say that more than 74,000 metric tons of these gases have been released in the atmosphere. The gases include three new chlorofluorocarbons (CFCs) and one hydrochlorofluorocarbon (HCFC).

For the study, researchers looked at air samples obtained from polar firm snow- which is like a catalogue of atmospheric conditions that existed a century ago. They compared these air samples with air collected between 1978 and 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," Dr Johannes Laube from UEA's School of Environmental Sciences, said in a news release.

What's worse is that the concentration of these gases is rising. According to researchers, the sources of the gases might include chemicals used in insecticide production. 

Why worry over CFCs and HCFCs?

Chlorofluorocarbons (CFCs) have atoms of carbon, chlorine, and fluorine while hydrochlorofluorocarbons have additional hydrogen atoms. CFCs are nontoxic and non-flammable gases that emerged in the 1930s as compounds that could make refrigerators safer.

In 1974,  Professor F. Sherwood Rowland and Dr. Mario Molina from University of California showed that CFCs are a major source of inorganic reactive chlorine in the stratosphere.  Reactive chlorine destroy earth's protective shield- the ozone layer.  Ozone is a molecule with three oxygen atoms instead of two oxygen atoms in normal oxygen that we breathe.

The discovery of Antarctic ozone hole in 1985 led to the beginning of war on CFCs.  In 1987, some 27 countries signed the Montreal Protocol to Reduce Substances that Deplete the Ozone Layer.

HCFCs are only slightly better than CFCs because they have shorter atmospheric lifetime and release fewer reactive chlorine in to the stratosphere. HCFCs are "temporary solution," and international legislation wants all countries to phase-out production of these gases.

Learn more about the HCFC phase out schedule, here.

In the present study, researchers found that the emission of the newly discovered CFCs and HCFC is higher than other gases of the same families. However, the increase hasn't reached the 1980s levels when emission of these gases was about million tons a year.

"CFCs are the main cause of the hole in the ozone layer over Antarctica. Laws to reduce and phase out CFCs came into force in 1989, followed by a total ban in 2010. This has resulted in successfully reducing the production of many of these compounds on a global scale. However, legislation loopholes still allow some usage for exempted purposes," Laube added.

The study," Newly detected ozone depleting substances in the atmosphere," is published in the journal Nature Geoscience. The study is funded by Natural Environment Research Council (NERC), the National Centre for Atmospheric Science (NCAS), the European Union, and the Commonwealth Scientific and Industrial Research Organisation (CSIRO).