In a study published in Geophysical Research Letters, researchers led by Lancaster University estimated that around 335,500 tonnes of trifluoroacetic acid (TFA) were deposited from the atmosphere onto Earth’s surface between 2000 and 2022.
TFA belongs to the PFAS family of synthetic chemicals, often referred to as “forever chemicals” because they don't naturally degrade and can persist in the environment for long periods of time.
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Scientists are increasingly concerned about the impact on the environment, wildlife and human health, with a widespread presence of TFA detected in water, soil and even human blood and urine.
The researchers found that hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and some anaesthetic gases move through the atmosphere and break down over time, but many TFAs remain in the atmosphere for decades. As a result, TFA pollution is expected to continue rising, with annual production potentially peaking sometime between 2025 and 2100.
The researchers tested their model against real-world measurements, including rainwater samples and Arctic ice cores, with TFA detected in the Arctic traced back to CFC replacement chemicals, despite the region’s remoteness from major emission sources.
"CFC replacements have long lifetimes and are able to be transported in the atmosphere from their point of emission to remote regions such as the Arctic where they can breakdown to form TFA," said Lucy Hart lead author Lucy Hart, a PhD researcher at Lancaster University. "Studies have found increasing TFA levels in remote Arctic ice-cores and our results provide the first conclusive evidence that virtually all of these deposits can be explained by these gases."
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The study also identifies newer refrigerants, particularly HFO-1234yf, which is widely used in vehicle air-conditioning systems, as an increasingly important source of future TFA pollution.
