Nitrogen trifluoride global emissions estimated from updated atmospheric measurements

Nitrogen trifluoride (NF3) 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 NF3 in 2011 were 1.18 +/- 0.21 Gg.y(-1), or similar to 20 Tg CO2-eq.y(-1) (carbon dioxide equivalent emissions based on a 100-y global warming potential of 16,600 for NF3). 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(-2) over the prior decade. In terms of CO2 equivalents, current NF3 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 NF3 over hexafluoroethane (C2F6) in electronics manufacture is significant-emissions of between 53 and 220 Tg CO2-eq.y(-1) were avoided during 2011. Despite these savings, total NF3 emissions, currently similar to 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 NF3 emissions reduction strategies to keep pace with its increasing use and to slow its rising contribution to anthropogenic climate forcing.