CFC replacements are polluting the Arctic

Abstract

Most countries began phasing out ozone-depleting chlorofluorocarbons (CFCs) in the early 1990s under the Montreal Protocol on Substances That Deplete the Ozone Layer. Replacing these refrigerants and propellants did the trick—the ozone layer recovered. However, a new analysis of Arctic ice cores points to an unintended consequence of this regulation. Over the years, the compounds that replaced CFCs have been transported and transformed in the atmosphere, getting deposited far from their sources. As a result, short-chain fluorinated alkyl acids, which are highly mobile persistent organic pollutants, are accumulating in the Arctic, and likely all around the Northern Hemisphere (Geophys. Res. Lett. 2020, DOI: 10.1029/2020GL087535). York University atmospheric chemist Cora Young has previously found long-chain per- and polyfluoroalkyl substances (PFAS) in Arctic ice. In her new research, she focused on smaller compounds in this class, which haven’t been studied as much. Researchers had hypothesized that levels of these short-chain compounds were