Chemicals initially introduced to safeguard the ozone layer have inadvertently contributed to the widespread dissemination of a potentially hazardous “forever chemical” known as trifluoroacetic acid (TFA), according to a recent study. Researchers from Lancaster University have unveiled that replacement chemicals for chlorofluorocarbons (CFCs) and certain anaesthetics are responsible for the deposition of approximately 335,500 tonnes of TFA across the Earth’s surface from 2000 to 2022.
The study, published in the journal Geophysical Research Letters, highlights that the rate of TFA entering the environment continues to increase. This is attributed to the longevity of some CFC replacements, which can persist in the atmosphere for decades. Peak annual TFA production from these sources is projected to occur between 2025 and 2100.
Understanding TFA and Its Sources
Trifluoroacetic acid is part of a group of man-made chemicals known as per- and polyfluorinated alkyl substances (PFAS), often referred to as “forever chemicals” due to their persistence in the environment. The European Chemicals Agency has classified TFA as harmful to aquatic life, and it has been detected in human blood and urine. The German Federal Office for Chemicals has recently suggested that TFA could be toxic to human reproduction.
Despite some agencies deeming current environmental levels of TFA as non-threatening to humans, the potential for irreversible accumulation has prompted calls for its classification as a planetary boundary threat. The study’s lead author, Lucy Hart, emphasized,
“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.”
Research Methodology and Findings
The researchers utilized “chemical transport” modeling to simulate how chemicals move and transform in the atmosphere. Their model quantified TFA pollution resulting from the atmospheric breakdown of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), which are prevalent in refrigeration and as inhalation anaesthetics.
Despite the phasing out of these chemicals under international agreements like the Montreal Protocol and the Kigali Amendment, their atmospheric presence continues to rise. The model’s findings were corroborated with observational data from Arctic ice cores and rainwater measurements, revealing that nearly all TFA found in the Arctic originates from CFC replacement chemicals.
Lucy Hart noted,
“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.”
Implications for Midlatitude Regions and Emerging Sources
Beyond polar regions, the study also identified the emergence of HFO-1234yf, a chemical used in car air conditioning systems, as a significant and growing source of atmospheric TFA. Professor Ryan Hossaini of Lancaster University, a co-author of the study, explained,
“HFOs are the latest class of synthetic refrigerants marketed as climate-friendly alternatives to HFCs. A number of HFOs are known to be TFA-forming, and their growing use adds uncertainty to future levels of TFA in our environment.”
Professor Hossaini stressed the necessity of addressing environmental TFA pollution, citing its persistence and increasing levels. He called for a concerted international effort, including more extensive TFA monitoring.
Global Collaboration and Future Monitoring
The study was a collaborative effort involving researchers from institutions across the globe, including Lancaster University, the University of Leeds, and the University of California San Diego, among others. Dr. Stefan Reimann, whose team in Switzerland monitors TFA-forming F-gases, remarked,
“This study is outstanding, as it combines for the first time all the important sources of atmospheric TFA and has a global focus. With increasing use of HFOs, accumulation of TFA in water bodies will potentially grow, making long-term monitoring a necessity.”
As the understanding of TFA evolves, experts underscore the importance of continued research and international cooperation to mitigate the environmental impacts of these persistent chemicals. The study’s findings provide a crucial foundation for future policy and regulatory decisions aimed at protecting both the environment and public health.
