In what seems to be the bitterest of ironies there is growing evidence chemicals brought in to help protect our ozone layer have had the unintended consequence of spreading vast quantities of a potentially toxic ‘forever chemicals’ around the globe.

In a week that the UK government has begun consultation on new rules to limit the use of PFAs or “forever chemicals” atmospheric scientists, led by researchers at Lancaster University, have for the first time calculated that CFC replacement chemicals and anaesthetics are behind around a third of a million tonnes (335,500 tonnes) of a persistent forever chemical called trifluoroacetic acid (TFA) being deposited from the atmosphere across the Earth’s surface between the years 2000 and 2022.

And the rate of TFA entering the environment from these sources is continuing to grow as some of these CFC replacements survive for decades in our atmosphere, with peak annual TFA production from these sources estimated to be anywhere from between 2025 and 2100.

Their model quantified TFA pollution created by the breakdown in the atmosphere of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), which are used in refrigeration, as well as chemicals used as inhalation anaesthetics.

Although these chemicals (known as F-gases) are being phased out (following the Montreal Protocol and the later Kigali Amendment) their presence is still increasing in the atmosphere.

“Our study shows that CFC replacements are likely to be the dominant atmospheric source of TFA,” said Lucy Hart, PhD researcher at Lancaster University and lead author of the study. “This really highlights the broader risks that need to be considered by regulation when substituting harmful chemicals such as ozone-depleting CFCs.”

The team’s modelling shows that almost all of the TFA found in the Arctic, which is far away from known emission sources, is from CFC replacement chemicals and highlights the widespread nature of TFA pollution.

“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 Hart. “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.”

“HFOs are the latest class of synthetic refrigerants marketed as climate friendly alternatives to HFCs,” said Professor Ryan Hossaini of Lancaster University and co-author of the study. “A number of HFOs are known to be TFA-forming and the growing use of these chemicals for car air conditioning in Europe and elsewhere adds uncertainty to future levels of TFA in our environment.”

“There is a need to address environmental TFA pollution because it is widespread, highly persistent, and levels are increasing,” added Hossaini. “The rising levels of TFA from F-gases is striking. Although HFC use is gradually being phased down, this TFA source will remain with us for decades. There is an urgent need to understand other TFA sources and to assess TFA’s environmental impacts. This requires a concerted international effort, including more extensive TFA monitoring in the UK and elsewhere.”

There is no reason for the research’s conclusions to be disbelieved and comes as a huge blow to those which have sought to remove CFCs from the atmosphere and with it protect the ozone layer. It creates a new liability risk and one which is extremely complex.

Jon Guy, Editor,

Emerging Risks