CHF3 (HFC-23) Emission Trend Response to CHClF2 (HCFC-22) Production and Recent Emission Abatement Measures
B.R. Miller1, M. Rigby2, P. Krummel3, P. Steele3, L. Porter4, M. Leist3, P. Fraser3, A. McCulloch5, C. Harth6, P. Salameh6, J. Mühle6, R. Weiss6, R. Prinn2, S. ODoherty5, B. Greally5 and P. Simmonds5
1Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309; 303-497-6624, E-mail: ben.r.miller@noaa.gov
2Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, MA 02138
3Centre for Australian Weather and Climate Research, Aspendale, Victoria, Australia
4Australian Government Bureau of Meteorology, Melbourne, Victoria, Australia
5School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
6Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093
CHF3 (HFC-23) is an inevitable by-product of CHClF2 (HCFC-22) production for use in air conditioning/refrigeration and as feedstock in fluoropolymer manufacture. CHF3 has limited use in small emissive and non-emissive markets and thus historically this ‘waste’ gas was simply vented to the atmosphere following production at CHClF2 plants. Concern over its high Global Warming Potential of 14,800 (100-year horizon) has lead to international efforts to curb its emissions. We present emission and production estimates for both gases based on observations of lower-tropospheric CHF3 and CHClF2 mole fractions at the Advanced Global Atmospheric Gases Experiment (AGAGE) network of five remote in situ Gas Chromatography/Mass Selective Detector instruments and in archived air samples. We quantitatively attribute recent changes in CHF3 production to various sources.
Figure 1. AGAGE in situ atmospheric observations (2007-2009) of CHF3 at global monitoring sites and in the Cape Grim air archive (1978-2009) show a historically accelerating growth with a marked deceleration since 2006 (left axis). Inversion using the AGAGE 2D 12-box model yields CHF3 emission estimates (right axis). The sharp increase in CHF3 emissions during 2004-2006 results from a dramatic increase in CHClF2 production in Article 5 countries (predominantly China and India). The sharp decrease in CHF3 emissions since 2006 reflects a decrease in global CHClF2 production, destruction (incineration) of >6 Gg CHF3 yr-1 by Article 5 countries (China, India, South Korea, Argentina and Mexico) participation in the United Nations Framework Convention on Climate Change’s Clean Development Mechanism and emission reduction efforts by non-Article 5 countries.