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New man-made gasses threaten the ozone layer

Posted on by phlorum

New man-made gasses threaten the ozone layer

Scientists from the University of East Anglia have discovered evidence of four more man-made gasses that are contributing to the depletion of the ozone layer. The research has been published in the journal Nature Geoscience.

The researchers discovered the gases by analysing ice cores. Air extracted from these cores provides a natural archive of what was in the atmosphere up to 100 years ago. The team also assessed modern air samples from Cape Grim in Tasmania. They found that three of these gases are CFS, one is a hydrochlorofluorocarbon (HCFC), and that two of these gases are also accumulating at an alarming rate. They estimate that about 74,000 tonnes of these gases have been released into the atmosphere.

According to BBC News, lead researcher Dr Johannes Laube said:

“Our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are man-made. The identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer. We don’t know where the new gases are being emitted from and this should be investigated. Possible sources include feedstock chemicals for insecticide production and solvents for cleaning electronic components. What’s more, the three CFCs are being destroyed very slowly in the atmosphere – so even if emissions were to stop immediately, they will still be around for many decades to come”.

Scientists have acknowledged that the current concentrations of these new gases are small and they do not present an immediate concern. However, the source of these gases needs to be identified.

Prof Piers Forster, from the University of Leeds, is reported to have stated that:

“This paper highlights that ozone depletion is not yet yesterday’s story. The concentrations found in this study are tiny. Nevertheless, this paper reminds us we need to be vigilant and continually monitor the atmosphere for even small amounts of these gases creeping up, either through accidental or unplanned emissions. 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.”

The ozone layer is in the atmosphere between 15 and 30km above the Earth’s surface. The layer provides a vital role in blocking harmful UV rays.

In 1985 British scientist were the first to discover the ‘hole’ in the ozone layer. At the time evidence pointed to CFCs, often used in aerosols propellants and refrigeration. The global community reacted quickly, limiting the use of these via the Montreal protocol, and ended in a total world ban on their production by 2010.

The new gases

  • CFC-112, CFC112a, CFC-113a, HCFC-133a
  • CFC-113a has been listed as an “agrochemical intermediate for the manufacture of pyrethroids”, a type of insecticide once widely used in agriculture
  • CFC-113a and HCFC-133a are intermediaries in the production of widely used refrigerants
  • CFC-112 and 112a may have been used in the production of solvents used to clean electrical components
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