CFC-replacements introduced in to assist shield our ozone layer have unintentionally unfold 1000’s of tonnes of poisonous ‘without end chemical substances’ all over the world, research finds
Chemicals brought in to help protect the ozone layer have inadvertently spread huge quantities of toxic ‘forever chemicals’ around the globe, a new study reveals.
Back in the 1980s, experts discovered that coolants used in fridges and car air conditioners were ruining the ozone – the protective layer that shields Earth from the sun’s harmful UV rays.
In a worldwide push, these substances, called CFCs, were replaced by chemicals that were thought to be more environmentally friendly.
But atmospheric scientists have now calculated that the new products have unintentionally spread 335,500 tonnes of toxic ‘forever chemicals’ around the world.
Studies have already indicated that this persistent ‘forever chemical’, called trifluoroacetic acid (TFA), is harmful for humans.
It has been detected in human blood and urine, and experts recently proposed that it be classified as potentially toxic to human reproduction.
‘Our study shows that CFC replacements are likely to be the dominant atmospheric source of TFA,’ lead author Lucy Hart, from Lancaster University, said.
‘This really highlights the broader risks that need to be considered by regulation when substituting harmful chemicals such as ozone–depleting CFCs.’
TFA production from HCFCs and HFCs increased 3.5-fold between the years 2000 and 2022, the team discovered
Although these chemicals are now also being phased out, their presence is still increasing in the atmosphere
Scientists behind the study, published in the journal Geophysical Research Letters, used ‘chemical transport’ modelling, which simulates how chemicals move about and change in the atmosphere.
They found that large amounts of TFA was being produced by the breakdown of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), which are now used in refrigeration, as well as chemicals used as inhalation anaesthetics.
TFA production from these sources increased 3.5–fold between the years 2000 and 2022, they discovered.
Their modelling even shows that almost all of the TFA found in the Arctic, which is far away from known emission sources, is from CFC replacement chemicals.
This highlights the widespread nature of TFA pollution, they warned. TFA is a type of per– and polyfluoroalkyl substance (PFAS), a group of human–made chemicals that can take over a thousand years to break down.
‘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,’ Ms Hart said.
‘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.’
Although these chemicals are now also being phased out, their presence is still increasing in the atmosphere.
Back in the 1980s, experts discovered that coolants used in the likes of fridges and car air conditioners were ruining the ozone – the protective layer that shields Earth from the sun’s harmful UV rays. Pictured: The ozone hole over Antarctica on November 1, 2025
The researchers also found evidence that HFO–1234yf, which is used in car air conditioning systems, as an important and likely growing source of TFA from the atmosphere.
‘HFOs are the latest class of synthetic refrigerants marketed as climate friendly alternatives to HFCs,’ said Professor Ryan Hossaini, 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.’
Although some agencies consider that current environmental TFA is below levels that would cause harm to humans, the potentially irreversible accumulation of TFA in the environment has led for calls for it to be designated as a planetary boundary threat.
‘Although HFC use is gradually being phased down, this TFA source will remain with us for decades,’ Professor Hossaini added.
‘There’s 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.’
Last year, researchers revealed that TFA had been detected in major rivers across the UK.
31 out of the 32 rivers tested contained traces of TFA, the researchers found. They warned people will be drinking water containing the chemical ‘every day’
Researchers analysed samples from 32 rivers across the UK’s four nations and found traces of trifluoroacetic acid (TFA) in 31 of them.
‘This molecule is everywhere,’ Alistair Boxall, professor of Environmental Science at the University of York, told the BBC.
‘We will all be drinking water containing TFA every day – so we’ll be exposed throughout our lifetime.
‘It’s that long–term, low level exposure that is the big concern.’
The Ozone layer sits in the stratosphere 25 miles above the Earth’s surface and acts like a natural sunscreen
Ozone is a molecule comprised of three oxygen atoms that occurs naturally in small amounts.
In the stratosphere, roughly seven to 25 miles above Earth’s surface, the ozone layer acts like sunscreen, shielding the planet from potentially harmful ultraviolet radiation that can cause skin cancer and cataracts, suppress immune systems and also damage plants.
It is produced in tropical latitudes and distributed around the globe.
Closer to the ground, ozone can also be created by photochemical reactions between the sun and pollution from vehicle emissions and other sources, forming harmful smog.
Although warmer-than-average stratospheric weather conditions have reduced ozone depletion during the past two years, the current ozone hole area is still large compared to the 1980s, when the depletion of the ozone layer above Antarctica was first detected.
In the stratosphere, roughly seven to 25 miles above Earth’s surface, the ozone layer acts like sunscreen, shielding the planet from potentially harmful ultraviolet radiation
This is because levels of ozone-depleting substances like chlorine and bromine remain high enough to produce significant ozone loss.
In the 1970s, it was recognised that chemicals called CFCs, used for example in refrigeration and aerosols, were destroying ozone in the stratosphere.
In 1987, the Montreal Protocol was agreed, which led to the phase-out of CFCs and, recently, the first signs of recovery of the Antarctic ozone layer.
The upper stratosphere at lower latitudes is also showing clear signs of recovery, proving the Montreal Protocol is working well.
But the new study, published in Atmospheric Chemistry and Physics, found it is likely not recovering at latitudes between 60°N and 60°S (London is at 51°N).
The cause is not certain but the researchers believe it is possible climate change is altering the pattern of atmospheric circulation – causing more ozone to be carried away from the tropics.
They say another possibility is that very short-lived substances (VSLSs), which contain chlorine and bromine, could be destroying ozone in the lower stratosphere.
VSLSs include chemicals used as solvents, paint strippers, and as degreasing agents.
One is even used in the production of an ozone-friendly replacement for CFCs.
