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
Received: 11 Jun 2012 – Discussion started: 25 Jul 2012
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.
Revised: 05 Oct 2012 – Accepted: 05 Oct 2012 – Published: 01 Nov 2012
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Saikawa, E., Rigby, M., Prinn, R. G., Montzka, S. A., Miller, B. R., Kuijpers, L. J. M., Fraser, P. J. B., Vollmer, M. K., Saito, T., Yokouchi, Y., Harth, C. M., Mühle, J., Weiss, R. F., Salameh, P. K., Kim, J., Li, S., Park, S., Kim, K.-R., Young, D., O'Doherty, S., Simmonds, P. G., McCulloch, A., Krummel, P. B., Steele, L. P., Lunder, C., Hermansen, O., Maione, M., Arduini, J., Yao, B., Zhou, L. X., Wang, H. J., Elkins, J. W., and Hall, B.: Global and regional emission estimates for HCFC-22, Atmos. Chem. Phys., 12, 10033-10050, doi:10.5194/acp-12-10033-2012, 2012.