The countries – Germany, the Netherlands, Norway, Sweden and Denmark – are seeking feedback on their proposal by September 19.
Researchers see a 33-fold increase in atmospheric TFA globally and up to 250-fold across Europe.
HFO-1234ze, marketed as a replacement refrigerant for HFCs, could produce significant amounts of an HFC with a GWP of more than 12,000, the study says.
The agency found significantly higher concentrations of TFA, an HFO byproduct, in rainwater.
ECOS calls for use of natural refrigerants, not HFOs and other new F-gases, whose climate impact is often understated.