Trifluoroacetic acid from fluorinated refrigerants contaminates rainwater

Urgent need for switch to natural refrigerants

A lot of room air conditioners hangig on the face of a buildingClick to enlarge
Room air conditioners contain environmentally harmful HFCs and use a lot of electricity.
Source: kanvag / Fotolia.com

As stipulated in the F-Gas Regulation, the use of climate-damaging fluorinated refrigerants and blowing agents must be significantly reduced in the European Union by 2030. Fluorinated gases are often replaced by short-lived fluorinated substances with lower Global Warming Potentials. However, these substances form trifluoroacetic acid (TFA) as a degradation product. Current rainwater measurements commissioned by the German Environment Agency (UBA) show that TFA concentrations have risen sharply since the 1990s. TFA is highly mobile, classified as hazardous to water and penetrates into groundwater and drinking water. There is currently no known method by which TFA could be removed from the water cycle by reasonable means - not even in drinking water treatment. UBA therefore recommends using natural refrigerants such as carbon dioxide or hydrocarbons.

Fluorinated refrigerants and blowing agents escape into the atmosphere from refrigeration and air conditioning systems, plastic foams and sprays, among other sources. Short-lived fluorinated refrigerants and propellants such as R1234yf, R1234ze(E) and R1233zd(E) are already being detected more frequently and in increasing quantities. Atmospheric degradation of fluorinated gases also produces trifluoroacetic acid (TFA). A study commissioned by UBA has modelled the quantitative development of fluorinated refrigerants and propellants and their atmospheric degradation products for the EU up to the year 2050. A three to four-fold increase in the TFA load from refrigerant emissions to up to 50,000 tonnes is predicted for Europe in 2050. The main factor driving this is the replacement of the F-gas R134a by the refrigerant R1234yf, which forms about 5 times more TFA than R134a.

To assess the TFA inputs from precipitation, samples from 8 measuring stations of the German Meteorological Service were analysed for the first time over a period of two years. The mean monthly TFA precipitation concentrations reached up to 4.87 micrograms per litre.

One-year TFA inputs amounted to 190 g/km² in 2018/19 and 276 g/km² in 2019/20, an increase of at least three to four times compared to the period 1995/96 (54 to 69 g/km²).

The model calculation indicates that in 2050 the refrigerant R1234yf alone is expected to cause TFA inputs from precipitation of 2.5 kg/km2 per year for Europe and up to 4 kg/km2 per year for Germany; this would correspond to a tenfold increase in today's TFA inputs.

"If manufacturers and operators now change over to systems using natural substances with a low global warming potential, such as hydrocarbons, carbon dioxide or ammonia, both the emissions of TFA can be significantly reduced and the climate can be protected," says UBA President Dirk Messner.

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Background

The F-Gas Regulation marked the beginning of the phase-out of fluorinated greenhouse gases in Europe in 2006. In 2016, the international community of states committed to reducing certain fluorinated greenhouse gases in the Montreal Protocol under the Kigali Agreement. Details on the process and UBA's recommendations on this can be found in an UBA press release.

 

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