HFOs are being internationally recognised as very good refrigerants, foam blowing agents, solvents and aerosol propellants due to their good balance of safety and environmental properties and their technical performance. Due their relatively recent commercialisation it is only to be expected and indeed necessary that their properties continue to be studied. The recent study for the Norwegian Environmental Agency runs to 349 pages (including appendices) and like many studies covers a several different aspects which can be used individually or collectively to lend support to a range of different positions.
The Norwegian Environmental Agency announced on its website that:
“The project concluded that an increasing use of HFO refrigerants is expected to have a negligible effect on the environment. However, the project highlighted a number of knowledge gaps that need to be addressed during any future studies.”
Nevertheless, one finding of the Study, has been used selectively and publicised on the hydrocarbons21 website:
”The risk, therefore, increases if emissions of HFO-1234yf to the environment increase. Therefore, phasing out HFOs (and consequently TFA), or emission reduction strategies along with best practise measures that help ensure efficient capturing of HFO/TFA during recycling operations, will help reduce the risk to human and environmental health.”
Given these facts, the conclusion on Hydrocarbons21 is overly broad. Indeed, it is at odds with that of the Environmental Effects Panel of the Montreal Protocol in establishing the environmental context of trifluoroacetic acid (TFA) potentially formed from HFCs (and HFOs) June 2015 (which you can find on our website and here (Montreal Protocol Informal B. Ecological Issues) for the complete briefing note and references). The Panel writes:
“While it is well established that TFA is a ubiquitous natural component in rivers, lakes, and other surface water bodies, uncertainties remain regarding anthropogenic sources, long-term fate and abundances as these are linked to current and future use and emissions of HFCs, HCFCs, and HFOs. Based on estimates to 2040, increases are predicted to remain relatively low and are therefore not expected to be a significant risk to human health or detrimental to the environment.“
Returning to the Study for the Norwegian Environmental Agency, there are a couple of issues that are worth highlighting: The study covers HFOs and their breakdown products, but also discusses the manufacture and use of TFA itself, which makes it difficult for the reader to separate out the two sources and their estimated consequences. Secondly HFOs are not all created equal in terms of breakdown products. The study lists only one widely used HFO (HFO-1234yf) that has TFA as a major breakdown product; others, like HFO-1234ze, break down in the atmosphere without yielding any or negligible quantities of TFA. Thirdly the study lists HFO-1216 (hexafluoropropene) as breaking down to form TFA. Hexafluoropropene is not used as a refrigerant, only as an intermediate consumed in the manufacture of other substances, including fluoropolymers, in highly regulated chemical manufacturing sites, with typically very low emissions.
So where does EFCTC stand on HFOs and TFA? We support good science and thorough investigation of the properties of all fluorochemicals produced by our member companies, including HFOs. We fully endorse emission reduction strategies during use along with best practice measures that help ensure efficient capturing of HFOs during recycling operations. There will be more studies into the environmental impacts of HFOs, but we should not lose sight of their good balance of safety and performance properties and their insignificant impact on the climate because they degrade rapidly in the atmosphere.