Articles | Volume 12, issue 21
Atmos. Chem. Phys., 12, 10033–10050, 2012
Atmos. Chem. Phys., 12, 10033–10050, 2012

Research article 01 Nov 2012

Research article | 01 Nov 2012

Global and regional emission estimates for HCFC-22

E. Saikawa1, M. Rigby1,2, R. G. Prinn1, S. A. Montzka3, B. R. Miller3, L. J. M. Kuijpers4, P. J. B. Fraser5, M. K. Vollmer6, T. Saito7, Y. Yokouchi7, C. M. Harth8, J. Mühle8, R. F. Weiss8, P. K. Salameh8, J. Kim8,9, S. Li9, S. Park9, K.-R. Kim9, D. Young2, S. O'Doherty2, P. G. Simmonds2, A. McCulloch2, P. B. Krummel5, L. P. Steele5, C. Lunder10, O. Hermansen10, M. Maione11, J. Arduini11, B. Yao12, L. X. Zhou12, H. J. Wang13, J. W. Elkins3, and B. Hall3 E. Saikawa et al.
  • 1Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, MA, USA
  • 2School of Chemistry, University of Bristol, Bristol, UK
  • 3Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
  • 4Eindhoven Centre for Sustainability, Technical University Eindhoven, Eindhoven, The Netherlands
  • 5Centre for Australian Weather and Climate Research, CSIRO Marine and Atmospheric Research, Aspendale, Victoria, Australia
  • 6Laboratory for Air Pollution and Environmental Technology, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Dubendorf, Switzerland
  • 7National Institute for Environmental Studies, Tsukuba, Japan
  • 8Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA
  • 9Seoul National University, Seoul, South Korea
  • 10Norwegian Institute for Air Research, Kjeller, Norway
  • 11The University of Urbino, Urbino, Italy
  • 12Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing, China
  • 13Georgia Institute of Technology, Atlanta, GA, USA

Abstract. HCFC-22 (CHClF2, chlorodifluoromethane) is an ozone-depleting substance (ODS) as well as a significant greenhouse gas (GHG). HCFC-22 has been used widely as a refrigerant fluid in cooling and air-conditioning equipment since the 1960s, and it has also served as a traditional substitute for some chlorofluorocarbons (CFCs) controlled under the Montreal Protocol. A low frequency record on tropospheric HCFC-22 since the late 1970s is available from measurements of the Southern Hemisphere Cape Grim Air Archive (CGAA) and a few Northern Hemisphere air samples (mostly from Trinidad Head) using the Advanced Global Atmospheric Gases Experiment (AGAGE) instrumentation and calibrations. Since the 1990s high-frequency, high-precision, in situ HCFC-22 measurements have been collected at these AGAGE stations. Since 1992, the Global Monitoring Division of the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) has also collected flasks on a weekly basis from remote sites across the globe and analyzed them for a suite of halocarbons including HCFC-22. Additionally, since 2006 flasks have been collected approximately daily at a number of tower sites across the US and analyzed for halocarbons and other gases at NOAA. All results show an increase in the atmospheric mole fractions of HCFC-22, and recent data show a growth rate of approximately 4% per year, resulting in an increase in the background atmospheric mole fraction by a factor of 1.7 from 1995 to 2009. Using data on HCFC-22 consumption submitted to the United Nations Environment Programme (UNEP), as well as existing bottom-up emission estimates, we first create globally-gridded a priori HCFC-22 emissions over the 15 yr since 1995. We then use the three-dimensional chemical transport model, Model for Ozone and Related Chemical Tracers version 4 (MOZART v4), and a Bayesian inverse method to estimate global as well as regional annual emissions. Our inversion indicates that the global HCFC-22 emissions have an increasing trend between 1995 and 2009. We further find a surge in HCFC-22 emissions between 2005 and 2009 from developing countries in Asia – the largest emitting region including China and India. Globally, substantial emissions continue despite production and consumption being phased out in developed countries currently.

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