title: Multiannual top-down estimate of HFC-23 emissions in East Asia.
abstract: Trifluoromethane (CHF3, HFC-23), with a 100-year global warming potential (GWP) of 12400, is regulated under the Kyoto Protocol. HFC-23 emissions in East Asia, especially in China, are currently thought to represent the majority of global HFC-23 emissions. This study provides both a bottom-up emission inventory and the multiannual top-down estimate of HFC-23 emissions in East Asia during 2007-2012. The new bottom-up inventory yields improved simulated HFC-23 mixing ratios compared to previous bottom-up inventories. The top-down estimate uses inverse modeling to further improve the model-measurement agreement. Results show that China contributed 94-98% of all HFC-23 emissions in East Asia. Annual a posteriori emissions from China were around 6.3 Gg/yr during the period 2007-2010 after which they increased to 7.1 ± 0.7 Gg/yr in 2011 and 8.8 ± 0.8 Gg/yr in 2012. For the first time, this study also provides a top-down estimate of HFC-23/HCFC-22 (chlorodifluoromethane, CHClF2) coproduction ratios in non-CDM (Clean Development Mechanism) HCFC-22 production plants as well as in all HCFC-22 production plants in China.
authors.affiliation: †Norwegian Institute for Air Research, 2007 Kjeller, Norway.|‡State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: X
authors.initials: X
authors.lastname: Fang
authors.affiliation: †Norwegian Institute for Air Research, 2007 Kjeller, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Stohl
authors.affiliation: §National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yokouchi
authors.affiliation: ¶Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093-0244, United States.
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.affiliation: §National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Park
authors.affiliation: ‡State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: J
authors.initials: J
authors.lastname: Hu
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D005617:Chlorofluorocarbons, Methane / Q000032:analysis*; D005202:Asia, Eastern; D057232:Global Warming
chemical_list: D000393:Air Pollutants; D005617:Chlorofluorocarbons, Methane; C009755:fluorocarbon 22; C009554:fluoroform