Update on the PFAS restriction proposal and F-gases by the Norwegian Environment Agency
The Norwegian Environment Agency held a virtual briefing on 30th March providing an update on the PFAS restriction proposal and F gases. The briefing confirmed that HFC-152a and HFC-32 are outside the scope of the current working definition. However, two important points, in the presentation slides, would have benefited from additional reference sources. These are:
- The yield of TFA from HFO-1234ze(E) degradation and
- The environmental effects of TFA from HFO-1234yf
The virtual briefing is available at The universal PFAS restriction proposal and F-gases - Norwegian Environment Agency
The yield of TFA from HFO-1234ze(E) degradation
The virtual briefing provides a high-level overview of HFO degradation and uses HFO-1234ze(E) as an example with a ca. 10% yield of TFA, referencing the UBA report as the source. Following the UBA report publication, EFCTC analysed the most current peer reviewed scientific papers on the potential contribution of HFOs and HCFOs, containing the CF3CH= moiety, to existing and future TFA levels. The substances with the CF3CH= moiety reported as supplied on the EU market are HFO-1234ze(E), HFO-1336mzz and HCFO-1233zd. The EFCTC analysis concluded that a 10% TFA yield is a considerable overestimate and that the very low yields of TFA from these substances mean that their expected contribution to TFA in the environment is extremely small. The EFCTC analysis is available in the position paper “Published evidence supports very low yields of TFA from most HFOs and HCFOs.”
TFA in the environment
The virtual briefing stated that the transition from HFC 134a to HFO 1234yf in air conditioning in cars may lead to an increase in TFA concentrations in Europe but did not discuss if this would result in any environmental effects. The paper referenced in the virtual briefing compares HFC-134a with HFO-1234yf degradation in the atmosphere and finds that their surface distribution plots for TFA concentrations are in good agreement with other modelling studies both in concentration magnitudes and spatial distributions. This paper also explains that previous studies have examined the impacts of the degradation of HFC-134a and HFO-1234yf.
These referenced studies have similar conclusions about the effects of TFA from HFO-1234yf and in addition have been summarised in the 2020 conclusions of the Environmental Effects Assessment Panel (EEAP): “The current low concentration of trifluoroacetic acid (TFA) produced by the degradation of several hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs), is currently judged not to pose a risk to human health or to the environment”. A more recent paper reached a similar conclusion. Important conclusions from all these papers are in the separate news item in this newsletter “ANNEX to News item: Update on the PFAS restriction proposal and F-gases by the Norwegian Environment Agency Annex to this item.”
 UBA Final report Persistent degradation products of halogenated refrigerants and blowing agents in the environment: type, environmental concentrations, and fate with particular regard to new halogenated substitutes with low global warming potential | Umweltbundesamt.
 Holland, Rayne E T; Khan, M. A. H. ; Driscoll, Isabel ; Chhantyal-Pun, Rabi; Derwent, Richard G.; Taatjes, Craig A.; Orr-Ewing, Andrew J; Percival, Carl J.; Shallcross, Dudley E., “Investigation of the Production of Trifluoroacetic Acid from Two Halocarbons, HFC-134a and HFO-1234yf and Its Fates Using a Global Three-Dimensional Chemical Transport Model”; ACS Earth and Space Chemistry, Vol. 5, No. 4, 15.04.2021, p. 849 - 857