Pioneering study shows effective regulation and monitoring is key to tackling emissions of a super-greenhouse gas

New research has revealed factories globally are not properly destroying one of the most potent greenhouse gases emitted from the production of fluoropolymers like Teflon, and refrigerants.

The study investigated a known disparity between real and reported emissions of this gas, prompting calls for more countries to sign up to official agreements to limit emissions and for their Teflon factories to be independently audited to ensure compliance.

The study, published today in the journal Nature, scrutinised emissions of one of the most potent hydrofluorocarbon (HFC) greenhouse gases called trifluoromethane, also known as HFC-23. Its main source is as a by-product in the industrial production of certain refrigerants and Teflon, which is used in products such as nonstick cookware. More than 150 countries have pledged to significantly reduce their HFC-23 emissions as part of the Kigali Amendment to the Montreal Protocol.

Since 2020, all Teflon manufacturers are obligated to destroy the strong greenhouse gas. According to the reports of the individual countries producing these products, this is happening. On paper the global annual emissions of HFC-23 were only 2,000 tons in 2020 but the actual global emissions, shown in numerous studies, uncover a different picture. In 2020 alone, around 16,000 tons of the greenhouse gas were found to be released into the atmosphere.

To unravel this discrepancy, researchers from the University of Bristol in the UK, Empa in Switzerland, and the Netherlands Organisation for Applied Scientific Research compared HFC-23 levels reported by individual countries with actual levels emitted from a Teflon factory in the Netherlands. To record the emissions as comprehensively and accurately as possible, a novel technique was used. This involved releasing a tracer directly next to the factory: a non-toxic gas that does not occur in the atmosphere and decomposes within a few weeks. At a distance of around 25 kilometres, they then measured the concentrations of HFC-23 and other by-products of Teflon manufacture – and also the concentration of the tracer.

First author Dr Dominique Rust, a Research Associate at the University of Bristol, said: “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.”

Results showed that even though estimated emissions are higher than those reported by the factory, measures to curb HFC-23 levels are largely effective.

Dr Rust, who worked on the study as part of her doctorate at Empa, the Swiss Federal Laboratories for Materials Science and Technology, added: “The collaboration with the Teflon manufacturer and the Dutch authorities was key to understanding the real picture.”

Co-author Dr Martin Vollmer, Researcher at Empa, said: “We suspect higher actual readings in the global atmosphere are explained by some countries underreporting emissions, resulting in this disconnect. One explanation is that abatement technologies aren’t as effectively implemented globally as at the factory we investigated."

The researchers are calling for factories to be independently audited. This independent verification of greenhouse gas emissions from the production of fluoropolymers and refrigerants would help close gaps in understanding the emission sources and check that countries are fully compliant under different international climate and environment agreements.

Co-author Dr Kieran Stanley, Senior Research Fellow at the University of Bristol, said: "Studies like this can help us to independently verify reported declines in emissions from fluorochemical plants and ensure that countries are reaching their obligations under the Kigali Amendment to the Montreal Protocol.

"These results are therefore really encouraging and show that abatement of emissions from fluorochemical plants producing fluoropolymers like Teflon can significantly reduce emissions of a highly potent greenhouse gas.”

The researchers are now planning another study in South Korea in October which will involve using the tracer method to determine the emissions of other halogenated substances in the capital city Seoul.