Scientists discover four new ODS gases
UK: Mystery surrounds the source of four new ozone depleting substances detected in the atmosphere and said to be rising fast.
A team led by Johannes Laube at the University of East Anglia’s Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, says the team detected the four ozone-depleting substances by analysing air trapped in snow in Greenland and air samples from Tasmania, Australia. Their analysis shows that the four chemicals discovered in the atmosphere for the first time – CFC-112, CFC-112a, CFC 113a and HCFC-133a – are being emitted in the northern hemisphere, but not precisely where or by whom.
The total emissions of these gases are still small but are rising fast. R113a, in particular. more than doubled between 2010 and mid-2012.
In total it is estimated that at least 74,000 tonnes of the four newly discovered chemicals were emitted before 2012, although this is relatively insignificant compared to the 1,000,000 tons of other CFCs that were pumped into the atmosphere per year in the 1980s. The amounts now detected are also said to be less than 1% of those emitted before the Montreal Protocol was signed.
Other scientists put the revelations into perspective. Quoted on the New Scientist website, Steve Montzka at the US National Oceanic and Atmospheric Administration in Boulder, Colorado, said. “We are talking about very minor releases. The paper’s benefit is to put these compounds on our radar to help ensure they don’t become significant.”
While their direct use is banned throughout the world or, in the case of HCFCs in the final stages of phase-out, ODS substances are still used as feedstock for the manufacture of a diverse range of products, including refrigerants, foam blowing agents, solvents, polymers, pharmaceuticals and agricultural chemicals.
CFC113a is used in the manufacture of R134a and the refrigerant blend component R125. The HCFC 133a is also used in the manufacture of R134a.
In a review of ozone protection issues facing the Montreal Protocol, UNEP’s Technology and Economic Assessment Panel (TEAP) has previously reported a rapid growth in the use of ODS feedstock, particularly HCFCs, and noted that feedstock use and emissions pose several issues in the medium-term:
In a 2009 report, it said: “As a result of this growth, the emissions arising from feedstock uses are taking on greater importance. It will be necessary to understand the magnitude of these emissions over time, and to identify options for avoiding them if these uses are to continue without harming the ozone layer.”