A new study by European researchers has found that byproduct emissions of super greenhouse refrigerant gas HFC-23 could be substantially reduced if abatement technology is properly employed during the production of polytetrafluoroethylene (PTFE), also known as Teflon, and refrigerants like HCFC-22. It called for a global audit of these plants’ HFC-23 abatement methods.
Destruction of HFC-23, an extremely potent global-warming gas with a 100-year GWP of 14,600 (IPCC, AR6), is mandatory for parties to the Kigali Amendment to the Montreal Protocol, the 2016 global agreement to phase down HFCs. Since 2020, all Teflon manufacturers are obligated to destroy HFC-23. Appropriate disposal of HFC-23 could cut its emissions by at least 85% –equivalent to 17% of CO2e emissions from global aviation, said the study.
The study – “Effective realization of abatement measures can reduce HFC-23 emissions” – was published on August 21 in the journal Nature. It concluded that many Teflon factories are failing to properly destroy HFC-23, contributing to its outsized presence in the atmosphere.
The study was conducted by Empa, (Swiss Federal Laboratories for Materials Science and Technology), the University of Bristol and the Netherlands Organization for Applied Scientific Research (TNO). It concludes that “abatement measures work – but are not being implemented everywhere,” according to an article on the Empa website.
According to reports provided by manufacturers, global emissions of HFC-23 in 2020 were 2,000 tons. However, actual global emissions in 2020 as determined in numerous assessments were around 16,000 tons, the study said.
To explain the discrepancy, the researchers looked at HFC-23 emissions from a Teflon factory in the Netherlands. Teflon, used widely in non-stick cookware, is part of the chemical group known as PFAS (per- and polyflouroaklyl substances), which are being scrutinized by regulators for their harmful health effects.
As explained by the Empa article, the researchers used a “novel method” to accurately record the factory’s HFC-23 emissions. Next to the factory they released a non-toxic “tracer gas” that does not occur in the atmosphere and decomposes within a few weeks.
At a distance of around 25km (15.5mi), they measured the concentrations of HFC-23 and other byproducts of Teflon production as well as the concentration of the tracer. “Since we knew exactly how much tracer we had released and how much of it arrived at the measuring point, we were able to calculate the emissions of HFC-23 and other gases,” said the study’s first author, Dominique Rust, a Research Associate at the University of Bristol who worked on the project as part of her doctorate at Empa.
The factory uses abatement measures to curb its HFC-23 emissions, burning the gas before it can escape. The study showed that emissions measured were higher than the ones the factory reported, but the amount emitted was still low, “showing that the abatement measures work well,” said Empa researcher Martin Vollmer.
Audits of Teflon factories requested
Given the high measurements of HFC-23 in the atmosphere, the study suggested that other Teflon factories may not be applying adequate abatement measures. The authors of the study call on countries to have their Teflon factories independently audited. “Such independent verification of GHG emissions from the production of fluoropolymers and coolants are needed to help close the gaps in our understanding of emission sources and check that countries are fully compliant under different international climate and environment agreements,” said co-author Kieran Stanley, Senior Research Fellow, the University of Bristol..
Empa researchers are planning another study in South Korea in October, when they will use the tracer method to determine the emissions of halogenated substances in the capital, Seoul.
A separate study published in April in the journal ChemSusChem also attempted to explain the larger- than-expected concentrations of HFC-23 in the atmosphere. It points to a link between the long-term fate of HFO degradation products in the atmosphere and the formation of HFC-23.
Meanwhile, in July, the Environmental Investigation Agency (EIA) called for “strengthened controls” under the Montreal Protocol to reduce fluorochemical greenhouse gas emissions from “unreported, unaccounted for and unexpected” sources.
The European Fluorocarbons Technical Committee, which represents f-gas manufacturers, did not respond to a request for comment for this article.
“Such independent verification of GHG emissions from the production of fluoropolymers and coolants are needed to help close the gaps in our understanding of emission sources and check that countries are fully compliant under different international climate and environment agreements.”
Kieran Stanley, Senior Research Fellow, the University of Bristol
