Nitrogen trifluoride global emissions estimated from updated atmospheric measurements

Abstract

Nitrogen trifluoride (NF[subscript 3]) has potential to make a growing contribution to the Earth’s radiative budget; however, our understanding of its atmospheric burden and emission rates has been limited. Based on a revision of our previous calibration and using an expanded set of atmospheric measurements together with an atmospheric model and inverse method, we estimate that the global emissions of NF[subscript 3 ] in 2011 were 1.18 ± 0.21 Gg⋅y[superscript −1], or ∼20 Tg CO[subscript 2]-eq⋅y[superscript−1] (carbon dioxide equivalent emissions based on a 100-y global warming potential of 16,600 for NF[subscript 3]). The 2011 global mean tropospheric dry air mole fraction was 0.86 ± 0.04 parts per trillion, resulting from an average emissions growth rate of 0.09 Gg⋅y[superscript −2] over the prior decade. In terms of CO[subscript 2] equivalents, current NF[subscript 3] emissions represent between 17% and 36% of the emissions of other long-lived fluorinated compounds from electronics manufacture. We also estimate that the emissions benefit of using NF[subscript 3] over hexafluoroethane (C[subscript 2]F[subscript 6]) in electronics manufacture is significant—emissions of between 53 and 220 Tg CO[subscript 2]-eq⋅y[superscript −1] were avoided during 2011. Despite these savings, total NF[subscript 3] emissions, currently ~10% of production, are still significantly larger than expected assuming global implementation of ideal industrial practices. As such, there is a continuing need for improvements in NF[subscript 3] emissions reduction strategies to keep pace with its increasing use and to slow its rising contribution to anthropogenic climate forcing.