Emissions of prohibited ozone-depleting gases were higher than expected. Their sources, according to a study by scientists from the Massachusetts Institute of Technology, are household appliances and materials produced even before the ban was introduced. The work was published in the journal Nature Communications.
Freons are compounds of fluorine, hydrocarbons and other halogens that are constantly used as components of building materials until the mid-1980s. Then chemists from the Massachusetts Institute of Technology found that freons destroy the ozone layer and have already led to its partial destruction over Antarctica.
The 1987 Montreal Agreement banned the use of freons in industry. Over the next decades, scientists have found several dozen fluorine compounds that do not destroy the ozone layer, but are the strongest greenhouse gases, they affect the atmosphere tens of thousands of times stronger than carbon dioxide.
CFCU-11 and CFC-12 (also known as freon-11, freon-11 and 12, respectively) are also prohibited substances. In 2013, and then in 2018, scientists recorded a sharp increase in emissions of these substances into the atmosphere – it turned out that the reason for this was the activity of small factories for the production of refrigerators in China. In 2019, enterprises closed, but the growth of pollutant emissions continued.
In a new study, scientists found that most modern ozone-depleting gases are formed from already produced materials, such as building insulation foam, refrigerators and cooling systems.
According to the authors, the emissions from these materials slow down the restoration of the ozone layer by six years, and also are a source of emissions of about 9 million metric tons of carbon dioxide.