TFA from CFC replacements is trifluoroacetic acid formed when replacement refrigerants and some inhaled anesthetics break down in the atmosphere. It is a short‑chain PFAS that is highly persistent and accumulates in water; typical levels measured today are generally low for human health, but TFA is harmful to aquatic life and is increasing globally. A new modelling study estimates about 335,500 tonnes were deposited worldwide between 2000 and 2022, raising concern about long‑term build‑up and management needs (Lancaster University).
What is TFA?
Trifluoroacetic acid (TFA) is a highly persistent, mobile organic acid (CF3COOH) in the class of PFAS often called “forever chemicals.” In natural waters it largely exists as the TFA anion, which is very resistant to further degradation and is transported readily through rain and surface water. Unlike some long‑chain PFAS, TFA is not known for strong bioaccumulation, but its persistence means it can accumulate in the environment over time.
Regulators in Europe classify TFA as harmful to aquatic life, and Germany has proposed classifying it as potentially toxic to reproduction, while many agencies currently judge typical environmental levels as below thresholds of concern for humans (Lancaster University).
How does TFA from CFC replacements form?
To protect the ozone layer, the Montreal Protocol and its Kigali Amendment drove a transition away from CFCs to HCFC, HFC, and more recently HFO refrigerants, and similar fluorinated compounds are used as inhaled anesthetics. In the lower atmosphere, many of these fluorinated gases react with oxidants and sunlight, fragmenting into smaller molecules. Several of the resulting pathways yield TFA, which then dissolves into cloud water and returns to the surface via rain or dry deposition.
Evidence points to multiple contributors: legacy HCFC/HFC refrigerants, modern HFOs such as HFO‑1234yf used in vehicle air conditioning, and certain inhaled anesthetics, all of which can ultimately generate TFA in varying amounts (Lancaster University; German Environment Agency).
How much TFA is being produced and where is it found?
The latest global chemical‑transport modelling attributes about 335,500 tonnes of atmospheric TFA deposition to CFC replacements and anesthetics between 2000 and 2022, with peak annual production projected later this century as long‑lived gases continue to degrade (Lancaster University).
Model–measurement comparisons indicate that nearly all TFA found in remote Arctic ice cores is explained by these atmospheric sources, underscoring long‑range transport and global dispersion. At mid‑latitudes, monitoring of rainwater and surface waters shows rising TFA, consistent with growing use of HFO‑1234yf in car air conditioning and ongoing degradation of older HCFCs and HFCs.
Although ozone assessments note that many observed concentrations are still low, the trend is upward and TFA’s persistence means environmental stocks can build faster than they are removed.
Is TFA dangerous to humans and ecosystems?
The current weight of evidence suggests different levels of concern for ecosystems and people:
- Aquatic ecosystems: TFA is classified as harmful to aquatic life and is highly mobile, so rising concentrations in lakes and rivers are an environmental concern, especially where dilution is limited.
- Human health: TFA is detected in rainwater, drinking water, and even human urine, but typical concentrations reported so far are generally below health‑based limits set or considered by some agencies. Scientific understanding is still evolving, and Germany has proposed a stricter reproductive toxicity classification to the EU system, reflecting precaution amid growing exposure.
- Persistence and irreversibility: Because TFA is very stable and water‑soluble, once released it is difficult to remove, which is why some scientists argue it should be treated as a potential planetary boundary concern.
In short, the immediate human‑health risk at typical current levels appears low in many places, but the combination of persistence, global spread, and ecological hazard warrants closer monitoring and management.
What can be done to limit TFA pollution?
- Prefer non‑fluorinated cooling where feasible: Expand use of alternative refrigerants such as CO2 (R744), ammonia (R717), or hydrocarbons (R290/propane) with proper safety engineering, reducing reliance on TFA‑forming F‑gases.
- Cut emissions from existing systems: Tighten leak prevention, recovery, and end‑of‑life destruction of HCFC/HFC/HFO refrigerants so less precursor reaches the atmosphere.
- Address anesthetic gases: Hospitals can choose lower‑impact agents, optimize fresh gas flows, and deploy capture and destruction technologies for exhaled anesthetics.
- Strengthen surveillance: Expand rainwater, surface water, groundwater, and remote‑region monitoring to track TFA trends and hotspots (German Environment Agency).
- Evaluate substitutes holistically: Require life‑cycle assessments that include TFA yields and persistence before approving new fluorinated chemicals, aligning climate goals under the Kigali Amendment with chemical‑safety objectives.
HFOs reduce ozone depletion and often have low direct global‑warming impact, but some are TFA‑forming; managing this trade‑off means pairing the Kigali phase‑down with stronger chemical‑risk evaluations and non‑fluorinated alternatives where practical.