NASA finds ozone-depleting chemical still being emitted

NASA is reportedly puzzled over why atmospheric concentrations of carbon tetrachloride (CC14) are still high despite the Montreal Protocol and a reduction in reported emissions.

The chemical is used in fire extinguishers and dry cleaning and was phased out as part of the Montreal Protocol and Vienna Convention on Protection of the Ozone Layer. That protocol was universally ratified in 2009.

However, studies have found that CC14 is still being emitted from a mysterious source. Emissions reached an average 39 kilotons per year. This amount is 30% of the peak emissions before the treaty came into effect.

In an article in phys.org, Qing Lang of NASA’s Godard Space Flight Center said: “It is now apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or unknown CC14 sources.”

Paul Newman, chief scientist for atmospheres at NASA, said: “People believe the emissions of ozone-depleting substances have stopped because of the Montreal Protocol. Unfortunately, there is still a major source of CC14 out in the world.”

The NASA study, which was published in the journal Geophysical Research Letters, also found that CC14 stays in the atmosphere 40% longer than had been previously estimated.

To read the article in phys.org, click here.