AN UPDATE ON FLUOROCARBONS

Dear subscribers,

In this EFCTC March 2025 newsletter, we report on the Environmental Effects Assessment Panel (EEAP) Update Assessment 2024 which provides an update on the atmospheric chemistry of HFCs and HFOs and discusses new measurements of concentrations of trifluoroacetic acid (TFA) in the environment. EEAP does not alter its previous assessments that HFOs have minimal contributions to the radiative forcing of climate change. EEAP also concludes that the risk to humans from chronic exposures to TFA in surface waters remains de minimis at current concentrations of TFA.

We explain why published indirect GWPs are overstated, due to formation of very small yields of HFC-23 from some HFOs and HCFOs from reaction with ozone. This is due to an oversight in the calculation method used in the published papers. The recalculated indirect GWPs are approximately half the published values, and we include a table comparing the published values with the recalculated indirect GWPs

We report that Genie Climatique Magazine has published an article stating that ten air-to-water scroll heat pumps using HFC-32 refrigerant and five screw compressor heat pumps using HFO R-1234ze(E) are installed at the Nanterre Arboretum near Paris. The Nanterre Arboretum is the largest wooden structure office complex in Europe and demonstrates the very latest in what is possible to reduce the embodied emissions from buildings by utilizing wood. The heat pumps, use groundwater as the energy source or sink with 10 geothermal wells cover 80% of the site's needs.

We summarise a paper investigating toxicological properties of investigated C2 (TFA) to C10 PFAS using in vitro assays. The paper demonstrated that the carbon chain length of PFAS can determine their in vitro toxicity and that ultrashort-chain PFAS (TFA) was found to be less toxic when compared to long-chain PFAS.

We report on a paper that explains separation technologies are essential to promoting the recycling and reuse of low GWP HFCs such as HFC-32, for example by separating it from HFC-125 in recovered HFC-410A. The paper reports on the development and modelling of composite hollow fibre membrane (HFM) separators for the selective separation of R-410A to obtain >95 mol % HFC-32 in a single membrane stage and demonstrates commercial potential for refrigerant gas separation. 

Finally, we report on a new Magnetic Resonance Imaging (MRI) chiller system, using HFC-32 refrigerant. MRI machines require precise and uniform cooling to maintain stable operating temperatures during scanning procedures, ensuring reliable and high-quality imaging results.

Do you want to learn more about EFCTC and fluorocarbons? More information is on the fluorocarbons.org website.

Thank you for your continued interest in EFCTC!

Environmental Effects Assessment Panel Update Assessment 2024

The Environmental Effects Assessment Panel (EEAP) Update Assessment 2024 [1] provides an update on the atmospheric chemistry of HFCs and HFOs and discusses new measurements of concentrations of trifluoroacetic acid (TFA) in the environment concluding that for HFOs the formation of CF3H (HFC-23) from photolysis of CF3CHO is of negligible importance and that CF3H generated by ozonolysis does not alter EEAP’s previous assessments that HFOs have minimal contributions to the radiative forcing of climate change. EEAP also concludes that the risk to humans from chronic exposures to TFA in surface waters remains de minimis at current concentrations of TFA.

Click "Read More" to read the full article.

Indirect GWPs of some HFOs and HCFOs from reaction with ozone: A recalculation

Two published papers [1, 2] discussed in the January 2025 EFCTC newsletter overstate the indirect GWPs of some HFOs and HCFOs from the formation of HFC-23 by reaction with ozone.  This is due to an oversight in the calculation method used. The olefinic bond (C=C bond) allows minor reactions with ozone (ozonolysis), and whilst these reactions are slow, HFC-23 may be produced in very small yields from some HFOs and some HCFOs. HFO-1234yf does not form any HFC-23 by reaction with ozone.

Click "Read More" to read the full article.

HFC-32 and HFO-1234ze heat pumps installed at Nanterre Arboretum

Ten air-to-water scroll heat pumps using HFC-32 refrigerant and five screw compressor heat pumps using HFO R-1234ze(E) are installed at the Nanterre Arboretum near Paris according to Genie Climatique Magazine [1]. The Nanterre Arboretum is the largest wooden structure office complex in Europe and includes 5 buildings with a wooden structure totalling 118,000 m² as well as two refurbished industrial buildings of 8,000 m².

Click "Read More" to read the full article.

C2 (TFA) - C10 PFAS: An in vitro comparison of toxicological mode of action

Varying carbon chain length and functional head-group of PFAS can affect their physicochemical properties, resulting in different toxicological properties.  A paper by Sodani et al. [1] investigated C2 (TFA) to C10 PFAS using in vitro assays. The paper demonstrated that the carbon chain length of PFAS can determine their in vitro toxicity and that ultrashort-chain PFAS (TFA) was found to be less toxic when compared to long-chain PFAS.

Click "Read More" to read the full article.