Atmospheric abundance and global emissions of perfluorocarbons CF 4 , C 2 F 6 and C 3 F 8 since 1800 inferred from ice core, firn, air archive and in situ measurements

• Published in: Atmospheric Chemistry and Physics
• Main Authors: C. M. Trudinger, P. J. Fraser, D. M. Etheridge, W. T. Sturges, M. K. Vollmer, M. Rigby, P. Martinerie, J. Mühle, D. R. Worton, P. B. Krummel, L. P. Steele, B. R. Miller, J. Laube, F. S. Mani, P. J. Rayner, C. M. Harth, E. Witrant, T. Blunier, J. Schwander, S. O'Doherty, M. Battle
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2016
• Subjects: Physics; QC1-999; Chemistry; QD1-999; South Pole; ice core; South pole
• Online Access: https://doi.org/10.5194/acp-16-11733-2016; https://doaj.org/article/51427deb627147648302756204f15ce3

Perfluorocarbons (PFCs) are very potent and long-lived greenhouse gases in the atmosphere, released predominantly during aluminium production and semiconductor manufacture. They have been targeted for emission controls under the United Nations Framework Convention on Climate Change. Here we present the first continuous records of the atmospheric abundance of CF 4 (PFC-14), C 2 F 6 (PFC-116) and C 3 F 8 (PFC-218) from 1800 to 2014. The records are derived from high-precision measurements of PFCs in air extracted from polar firn or ice at six sites (DE08, DE08-2, DSSW20K, EDML, NEEM and South Pole) and air archive tanks and atmospheric air sampled from both hemispheres. We take account of the age characteristics of the firn and ice core air samples and demonstrate excellent consistency between the ice core, firn and atmospheric measurements. We present an inversion for global emissions from 1900 to 2014. We also formulate the inversion to directly infer emission factors for PFC emissions due to aluminium production prior to the 1980s. We show that 19th century atmospheric levels, before significant anthropogenic influence, were stable at 34.1 ± 0.3 ppt for CF 4 and below detection limits of 0.002 and 0.01 ppt for C 2 F 6 and C 3 F 8 , respectively. We find a significant peak in CF 4 and C 2 F 6 emissions around 1940, most likely due to the high demand for aluminium during World War II, for example for construction of aircraft, but these emissions were nevertheless much lower than in recent years. The PFC emission factors for aluminium production in the early 20th century were significantly higher than today but have decreased since then due to improvements and better control of the smelting process. Mitigation efforts have led to decreases in emissions from peaks in 1980 (CF 4 ) or early-to-mid-2000s (C 2 F 6 and C 3 F 8 ) despite the continued increase in global aluminium production; however, these decreases in emissions appear to have recently halted. We see a temporary reduction of around 15 % in CF 4 emissions ...