Ozone-protecting substances are quietly raining a PFAS 'forever chemical' onto Earth

A chemical introduced into the atmosphere to help protect the ozone layer may have created a different environmental concern. 

Scientists have said some of the substitute gases have created "forever chemicals" that come back down in rainfall.

That means compounds used in cooling systems, air conditioners, and even some anesthetics could be contributing to a form of pollution that is extremely difficult to remove and may be spreading on a global scale.

What happened?

A report from Science Daily noted that from 2000 to 2022, chemicals used to replace ozone-damaging CFCs, along with certain inhaled anesthetics, led to an estimated 335,500 tonnes of trifluoroacetic acid, or TFA, being deposited from the air onto Earth's surface.

To reach that estimate, the Lancaster University team modeled what happens to HCFCs, HFCs, and inhaled-anesthetic compounds after they are released, following their movement through the atmosphere, their reactions with other chemicals, and their eventual deposition onto land and water.

Even though international agreements are phasing out many of these F-gases, their amounts in the atmosphere are continuing to climb, and some linger there for decades.

The analysis suggested that in the Arctic, where emissions are far away, these replacement chemicals may explain nearly all of the TFA that has been observed there.

Outside the polar regions, the study pointed to HFO-1234yf, used in vehicle air conditioning, as an increasingly troubling future source.

Why does it matter?

TFA belongs to the PFAS group, a class of chemicals often labeled "forever chemicals" because they resist breakdown and can remain in the environment for long periods.

Researchers are still trying to determine the full effects of TFA, but the European Chemicals Agency classified it as harmful to aquatic life, and it has also been detected in human blood and urine.

Some agencies have said current environmental concentrations are below levels expected to harm people. Even so, TFA continues to build up and may be difficult to remove once it becomes widespread in water and ecosystems.

The findings, published in the journal Geophysical Research Letters, add to broader questions about chemical substitution. Some compounds were adopted because they were safer for the ozone layer or better for the climate than earlier options, but that does not necessarily mean they are harmless in every other respect.

What does it mean?

Lead author Lucy Hart said, per Science Daily, "Our study shows that CFC replacements are likely to be the dominant atmospheric source of TFA."

She added: "This really highlights the broader risks that need to be considered by regulation when substituting harmful chemicals such as ozone-depleting CFCs."

Professor Ryan Hossaini was even more direct: "There is a need to address environmental TFA pollution because it is widespread, highly persistent, and levels are increasing." 

Meanwhile, co-author Dr. Stefan Reimann said, "In all regions where TFA measurements are available, a consistent picture of increasing atmospheric concentrations and deposition to Earth's surface is emerging."

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