ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-261-2012 Long-term tropospheric trend of octafluorocyclobutane (c-C<sub>4</sub>F<sub>8</sub> or PFC-318) Oram D. E. 1 Mani F. S. 2 Laube J. C. 2 Newland M. J. 2 Reeves C. E. 1 Sturges W. T. 2 Penkett S. A. 2 Brenninkmeijer C. A. M. 3 Röckmann T. 4 Fraser P. J. 5 National Centre for Atmospheric Science, School of Environmental Sciences, University of East Anglia, Norwich, UK School of Environmental Sciences, University of East Anglia, Norwich, UK Max Planck Institute for Chemistry, Air Chemistry Division, Mainz, Germany Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, The Netherlands Centre for Australian Weather and Climate Research/CSIRO Marine and Atmospheric Research, Aspendale, Australia 05 01 2012 12 1 261 269 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/12/261/2012/acp-12-261-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/261/2012/acp-12-261-2012.pdf

Air samples collected at Cape Grim, Tasmania between 1978 and 2008 and during a series of more recent aircraft sampling programmes have been analysed to determine the atmospheric abundance and trend of octafluorocyclobutane (c-C<sub>4</sub>F<sub>8</sub> or PFC-318). c-C<sub>4</sub>F<sub>8</sub> has an atmospheric lifetime in excess of 3000 yr and a global warming potential (GWP) of 10 300 (100 yr time horizon), making it one of the most potent greenhouse gases detected in the atmosphere to date. The abundance of c-C<sub>4</sub>F<sub>8</sub> in the Southern Hemisphere has risen from 0.35 ppt in 1978 to 1.2 ppt in 2010, and is currently increasing at a rate of around 0.03 ppt yr<sup>−1</sup>. It is the third most abundant perfluorocarbon (PFC) in the present day atmosphere, behind CF<sub>4</sub> (~75 ppt) and C<sub>2</sub>F<sub>6</sub> (~4 ppt). Although a number of potential sources of c-C<sub>4</sub>F<sub>8</sub> have been reported, including the electronics and semi-conductor industries, there remains a large discrepancy in the atmospheric budget. Using a 2-D global model to derive top-down global emissions based on the Cape Grim measurements yields a recent (2007) emission rate of around 1.1 Gg yr<sup>−1</sup> and a cumulative emission up to and including 2007 of 38.1 Gg. Emissions reported on the EDGAR emissions database for the period 1986–2005 represent less than 1% of the top-down emissions for the same period, which suggests there is a large unaccounted for source of this compound. It is also apparent that the magnitude of this source has varied considerably over the past 30 yr, declining sharply in the late 1980s before increasing again in the mid-1990s.

 References % vor jede Referenz Brenninkmeijer, C. A. M., Crutzen, P. J., Fischer, H., Güsten, H., Hans, W., Heinrich, G., Heintzenberg, J., Hermann, M., Immelmann, T., Kersting, D., Maiss, M., Nolle, M., Pitscheider, A., Pohlkamp, H., Scharffe, D., Specht, K., and Wiedensohler, A.: CARIBIC-Civil Aircraft for global measurement of trace gases and aerosols in the tropopause region, J. Atmos. Oceanic Technol., 16, 1373–1383, 1999. Brenninkmeijer, C. A. M., Crutzen, P., Boumard, F., Dauer, T., Dix, B., Ebinghaus, R., Filippi, D., Fischer, H., Franke, H., Frieß, U., Heintzenberg, J., Helleis, F., Hermann, M., Kock, H. H., Koeppel, C., Lelieveld, J., Leuenberger, M., Martinsson, B. G., Miemczyk, S., Moret, H. P., Nguyen, H. N., Nyfeler, P., Oram, D., O'Sullivan, D., Penkett, S., Platt, U., Pupek, M., Ramonet, M., Randa, B., Reichelt, M., Rhee, T. S., Rohwer, J., Rosenfeld, K., Scharffe, D., Schlager, H., Schumann, U., Slemr, F., Sprung, D., Stock, P., Thaler, R., Valentino, F., van Velthoven, P., Waibel, A., Wandel, A., Waschitschek, K., Wiedensohler, A., Xueref-Remy, I., Zahn, A., Zech, U., and Ziereis, H.: Civil Aircraft for the regular investigation of the atmosphere based on an instrumented container: The new CARIBIC system, Atmos. Chem. Phys., 7, 4953–4976, http://dx.doi.org/10.5194/acp-7-4953-2007doi:10.5194/acp-7-4953-2007, 2007. Culbertson, J. A., Prins, J. M., and Grimsrud, E. P.: Improvements in the detection and analysis of CF<sub>3</sub>-containing compounds in the background atmosphere using gas chromatography-high resolution mass spectrometry, J. Chromatogr., 903, 261–265, 2000. Culbertson, J. A., Prins, J. M., Grimsrud, E. P., Rasmussen, R. A., Khalil, M. A. K., and Shearer, M. J.: Observed trends for CF3-containing compounds in background air at Cape Meares, Oregon, Point Barrow, Alaska and Palmer Station, Antarctica, Chemosphere, 55, 1109–1119, 2004. Cunnold, D., Fraser, P. J., Weiss, R. F., Prinn, R. G., Simmonds, P. G., Miller, B. R., Alyea, F. N., and Crawford, A. J.: Global trends and annual releases of CCl<sub>3</sub>F and CCl<sub>2</sub>F<sub>2</sub> estimated from ALE/GAGE and other measurements from July 1978 to June 1991, J. Geophys. Res., 99, 1107–1126, 1994. DECC: UK Department of Energy and Climate Change, Statistical release for 2009, http://www.decc.gov.uk/ (last access: March 2011), 2011. Douslin, D. R., Moore, R. T., and Waddington, G.: The pressure-volume-temperature properties of perfluorocyclobutane: equations of state, virial coefficients and intermolecular potential energy functions, J. Phys. Chem., 63, 1959–1966, 1959. EDGAR, 2009: European Commission, Joint Research Centre (JRC)/Netherlands Environmental Assessment Agency (PBL). Emission Database for Global Atmospheric Research (EDGAR), release version 4.0., http://edgar.jrc.ec.europa.eu (last access March 2011), 2009. Engel A., Strunk, M., Müller, M., Haase, H.-P., Poss, C., Levin, I., and Schmidt, U.: Temporal development of total chlorine in the high-latitude stratosphere based on reference distributions of mean age derived from CO<sub>2</sub> and SF$_6$, J. Geophys. Res., 107, 4136, http://dx.doi.org/10.1029/2001JD000584doi:10.1029/2001JD000584, 2002. Fraser, P. J., Oram, D. E., Reeves, C. E., Penkett, S. A., and McCulloch, A.: Southern hemispheric halon trends (1978–1998) and global halon emissions, J. Geophys. Res., 104, 15985–15999, 1999. Forster, P., Ramaswamy, V., Artaxo, P., Berntsen, T., Betts, R., Fahey, D. W., Haywood, J. Lean, J., Lowe, D. C., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M., and Van Dorland, R.: Changes in Atmospheric Constituents and in Radiative Forcing, in: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2007. Geller, L. S., Elkins, J. W., Lobert, J. M., Clarke, A.D., Hurst, D. F. Butler, J. H., and Myers, R. C.: Tropospheric SF$_6$: Observed latitudinal distribution and trends, derived emissions and interhemispheric exchange time, Geophys. Res. Lett., 24, 675–678, 1997. Harnisch, J.: Atmospheric Perfluorocarbons: sources and concentrations, in Non-CO<sub>2</sub> greenhouse gases: scientific understanding, control and implementation, Proceedings of 2nd International Symposium on Non-CO<sub>2</sub> Greenhouse Gases (NCGG-2), Noordwijkerhout, The Netherlands, 8–10 September 1999, edited by: Van Ham, J., Baede, A. P. M., Meyer, L. A., and Ybema, R., 205–210, Kluwer Academic Publishers, The Netherlands, 2000. Harnisch, J. and Eisenhauer, A.: Natural CF<sub>4</sub> and SF$_6$ on earth, Geophys. Res. Lett., 25, 2401–2404, 1998. Harnisch, J., Borchers, R., Fabian, P., Gäggeler, H. W., and Schotterer, U.: Effect of natural tetrafluoromethane, Nature, 384, p 32, 1996. Hough, A. M.: The development of a two-dimensional global tropospheric model, 1, The model transport, Atmos. Environ., 23, 1235–1261, 1989. Hough, A. M.: Development of a two-dimensional global tropospheric model: Model chemistry, J. Geophys. Res., 96, 7325–7362, 1991. Kaiser, J., Engel, A., Borchers, R., and Röckmann, T.: Probing stratospheric transport and chemistry with new balloon and aircraft observations of the meridional and vertical N<sub>2</sub>O isotope distribution, Atmos. Chem. Phys., 6, 3535–3556, http://dx.doi.org/10.5194/acp-6-3535-2006doi:10.5194/acp-6-3535-2006, 2006. Khalil, M. A. K., Rasmussen, R. A., Culbertson, J. A., Prins, J. M., Grimsrud, E. P., and Shearer, M. J.: Atmospheric perfluorocarbons, Environ. Sci. Technol., 37, 4358–4361, 2003. Langenfelds, R. J., Fraser, P. J., Francey, R. J., Steele, L. P., Porter, L. W., and Allison, C. E.: The Cape Grim air archive: The first seventeen years, in Baseline 94–95, edited by: Francey, R. J., Dick, A. L., and Derek, N., 53–70, Bur. Meteorol. and CSIRO Atmos. Res., Melbourne, Victoria, Australia, 1996. Laube, J. C., Martinerie, P., Witrant, E., Blunier, T., Schwander, J., Brenninkmeijer, C. A. M., Schuck, T. J., Bolder, M., Röckmann, T., van der Veen, C., Bönisch, H., Engel, A., Mills, G. P., Newland, M. J., Oram, D. E., Reeves, C. E., and Sturges, W. T.: Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere, Atmos. Chem. Phys., 10, 5903–5910, http://dx.doi.org/10.5194/acp-10-5903-2010doi:10.5194/acp-10-5903-2010, 2010a. Laube, J. C., Engel, A., Bönisch, H., Möbius, T., Sturges, W. T., Braß, M., and Röckmann, T.: Fractional release factors of long-lived halogenated organic compounds in the tropical stratosphere, Atmos. Chem. Phys., 10, 1093–1103, http://dx.doi.org/10.5194/acp-10-1093-2010doi:10.5194/acp-10-1093-2010, 2010b. Maiss, M., Steele, L. P., Francey, R. J., Fraser, P. J., Langenfelds, R. L., Trivett, N. B. A., and Levin, I.: Sulfur hexafluoride - a powerful new atmospheric tracer, Atmos. Environ., 30, 1621–1629, 1996. Mani, F.: Measurements of $\delta $15N of nitrogen gas and composition of trace gases in air from firn and ice cores, Ph.D. Thesis, University of East Anglia, Norwich, UK, 2010. Miller, B., Huang, J., Weiss, R., Prinn, R., and Fraser, P.: Atmospheric trend and lifetime of chlorodifluoromethane (HCFC-22) and the global tropospheric OH concentration, J. Geophys. Res., 103, 13237–13248, 1998. Morisaki, S.: Simultaneous thermogravimetry-mass spectrometry and pyrolysis-gas chromatography of fluorocarbon polymers, Thermochimica Acta, 25, 171–183, 1978. Montzka, S. A., Fraser, P. J. (Lead Authors), Butler, J. H., Connell, P. S., Cunnold, D. M., Daniel, J. S., Derwent, R. G., Lal, S., McCulloch, A., Oram, D. E., Reeves, C. E., Sanhueza, E., Steele, L. P., Velders, G. J. M., Weiss, R. F., and Zander, R. J.: Controlled substances and other source gases, Chapter 1 in Scientific Assessment of Stratospheric Ozone Depletion: 2002, Global Ozone Research and Monitoring Project, Report No. 47, World meteorological Organisation, Geneva, 2003. Mühle, J., Ganesan, A. L., Miller, B. R., Salameh, P. K., Harth, C. M., Greally, B. R., Rigby, M., Porter, L. W., Steele, L. P., Trudinger, C. M., Krummel, P. B., O'Doherty, S., Fraser, P. J., Simmonds, P. G., Prinn, R. G., and Weiss, R. F.: Perfluorocarbons in the global atmosphere: tetrafluoromethane, hexafluoroethane, and octafluoropropane, Atmos. Chem. Phys., 10, 5145–5164, http://dx.doi.org/10.5194/acp-10-5145-2010doi:10.5194/acp-10-5145-2010, 2010. Oram, D. E.: Trends of long-lived anthropogenic halocarbons in the southern hemisphere and model calculations of global emissions, Ph.D. Thesis, University of East Anglia, Norwich, UK, 1999. Oram, D. E., Reeves, C. E., Fraser, P. J., and Penkett, S. A.: Measurements of HCFC-142b and HCFC-141b in the Cape Grim air archive: 1978–1993, Geophys. Res. Lett., 22, 2741–2744, 1995. Oram, D. E., Reeves, C. E., Sturges, W. T., Penkett, S. A., Fraser, P. J., and Langenfelds, R. L.: Recent tropospheric growth rate and distribution of HFC-134a (CF<sub>3</sub>CH<sub>2</sub>F), Geophys. Res. Lett., 23, 1949–1952, 1996. Oram, D. E., Sturges, W. T., Penkett, S. A., McCulloch, A., and Fraser, P. J.: Growth of fluoroform (CHF<sub>3</sub>, HFC-23) in the background atmosphere, Geophys. Res. Lett., 25, 35–38, 1998. Penkett, S. A., Prosser, N. J. D., Rasmussen, R. A., and Khalil, M. A. K.: Atmospheric measurements of CF<sub>4</sub> and other fluorocarbons containing the CF<sub>3</sub> grouping, J. Geophys. Res., 86, 5172–5178, 1981. Plumb, R. A. and Ko, M. K. W.: Interrelationships between mixing ratios of long-lived stratospheric constituents, J. Geophys. Res., 97, 10145–10156, 1992. Prinn, R. G., Weiss, R. F., Miller, B. R., Huang, J., Alyea, F. N., Cunnold, D. M., Fraser, P. J., Hartley, D. E., and Simmonds, P. G.: Atmospheric trends and lifetime of trichloroethane and global average hydroxyl radical concentrations based on 1978-1994 ALE/GAGE measurements, Science, 269, 187–192, 1995. Rasmussen, R. A., Penkett, S. A., and Prosser, N. J. D.: Measurement of carbon tetrafluoride in the atmosphere, Nature, 277, 549–551, 1979. Ravishankara, A. R., Solomon, S., Turnipseed, A. A., and Warren, R. F.: Atmospheric lifetimes of long-lived halogenated species, Science, 259, 194–199, 1993. Reeves, C. E., Sturges, W. T., Sturrock, G. A., Preston, K., Oram, D. E., Schwander, J., Mulvaney, R., Barnola, J.-M., and Chappellaz, J.: Trends of halon gases in polar firn air: implications for their emission distributions, Atmos. Chem. Phys., 5, 2055–2064, http://dx.doi.org/10.5194/acp-5-2055-2005doi:10.5194/acp-5-2055-2005, 2005. Saito T., Yokouchi, Y., Stohl, A., Taguchi, S., and Mukai, H.: Large emissions of perfluorocarbons in East Asia deduced from continuous atmospheric measurements, Environ. Sci. Technol., 44, 4089–4095, 2010. Sturges, W. T., Oram, D. E., Penkett, S. A., Fraser, P. J., and Engel, A.: Long-lived halogenated compounds in the stratosphere, Proceedings of 2nd International Symposium on Non-CO<sub>2</sub> Greenhouse Gases (NCGG-2), Noordwijkerhout, The Netherlands, 8–10 September 1999, edited by: Van Ham, J., A. P. M. Baede, L. A. Meyer, and Ybema, R., 239–240, Kluwer Academic Publishers, The Netherlands, 2000. Worton, D. R., Sturges, W. T., Gohar, L. K., Shine, K. P., Martinerie, P., Oram, D. E., Humphrey, S. P., Begley, P., Barnola, J.-M., Schwander, J., and Mulvaney, R.: Atmospheric trends and radiative forcings of CF<sub>4</sub> and C<sub>2</sub>F$_6$ inferred from firn air, Environ. Sci. Technol., 41, 2184–2189, http://dx.doi.org/10.1021/es061710tdoi:10.1021/es061710t, 2007.