Chemicals meant to protect the ozone layer may be spreading a 'forever chemical' worldwide

What was supposed to be a major environmental win for the ozone layer may have an unsettling side effect. 

New research suggests some of the chemicals introduced to replace ozone-depleting substances are now helping spread a persistent "forever chemical" worldwide.

What happened?

From 2000 through 2022, about 335,500 tonnes of trifluoroacetic acid, or TFA, were deposited from the atmosphere onto Earth's surface, according to estimates from a Lancaster University research team. The researchers traced the pollution to chemicals used in place of chlorofluorocarbons, or CFCs, as well as certain anesthetics.

To arrive at those findings, the team used chemical transport modeling to follow refrigerants and other gases as they moved through the atmosphere, reacted, and eventually returned to land and water through rainfall or direct deposition. 

TFA belongs to the PFAS family, a group of substances often called forever chemicals because they are extremely resistant to breaking down.

Their results showed that nearly all of the TFA detected in the Arctic could be attributed to these CFC replacement chemicals, even though the region is far from major emission sources.

Lead author Lucy Hart said, "Our study shows that CFC replacements are likely to be the dominant atmospheric source of TFA. This really highlights the broader risks that need to be considered by regulation when substituting harmful chemicals such as ozone-depleting CFCs."

The analysis also pointed to HFO-1234yf, a refrigerant widely used in car air conditioning, as a growing contributor outside the polar regions.

Why does it matter?

TFA is accumulating in the environment even as communities are already grappling with broader concerns about forever chemicals. While scientists are still studying its full health effects, the European Chemicals Agency classifies it as harmful to aquatic life, and researchers have found it in human blood and urine.

Some of the gases that create TFA can remain in the atmosphere for decades, meaning pollution could keep increasing for years. Scientists estimate yearly TFA production from these sources may peak sometime between 2025 and 2100.

Cooling systems are crucial for homes, hospitals, and cars, especially as extreme heat grows more severe, but chemical substitutes that solve one environmental problem can end up creating another.

Co-author Professor Ryan Hossaini said, "There is a need to address environmental TFA pollution because it is widespread, highly persistent, and levels are increasing."

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