Experimental determination of the global warming potential of carbonyl fluoride

Abstract. Carbonyl fluoride (COF₂) has recently attracted attention as a potential low-global-warming-potential (GWP) replacement for high-GWP fluorinated gases (F-gases) used in semiconductor and display manufacturing, such as HFCs, PFCs, SF₆, and NF₃, because of its proven efficacy as a chamber-cleaning gas and rapid hydrolysis in moist air. In this study, the infrared absorption cross-section (ACS) of COF₂ was measured using Fourier-transform infrared spectroscopy, and its radiative efficiency (RE) was calculated using a revised form of the Pinnock curve that incorporates stratospheric temperature adjustment, yielding 0.1413 W·m⁻²·ppb⁻¹. Atmospheric lifetimes of COF₂ determined from kinetic decay profiles were 7.56 h, 36.67 min, and 54.86 min for dry synthetic air (O₂-only), high-humidity, and low-humidity conditions, respectively, corresponding to GWP₁₀₀ values of 0.1018, 0.0082, and 0.0117, respectively. Accordingly, in moist tropospheric air, COF₂ exhibited GWP₁₀₀ <1. These results demonstrate that water vapor-driven hydrolysis overwhelmingly governs COF₂ removal in the atmosphere, leading to a substantially shorter lifetime and far lower GWP than conventional F-gases. Furthermore, since CO₂ is the confirmed terminal degradation product, the ultimate climate impact of COF₂ is equivalent to that of CO₂ on a molar basis. This study presents one of the most comprehensive experimental analyses of COF₂ and offers a robust evaluation of its GWP and its potential as a sustainable alternative for reducing the climate footprint of semiconductor and display manufacturing processes.