title: High-global warming potential F-gas emissions in California: comparison of ambient-based versus inventory-based emission estimates, and implications of refined estimates.
abstract: To provide information for greenhouse gas reduction policies, the California Air Resources Board (CARB) inventories annual emissions of high-global-warming potential (GWP) fluorinated gases, the fastest growing sector of greenhouse gas (GHG) emissions globally. Baseline 2008 F-gas emissions estimates for selected chlorofluorocarbons (CFC-12), hydrochlorofluorocarbons (HCFC-22), and hydrofluorocarbons (HFC-134a) made with an inventory-based methodology were compared to emissions estimates made by ambient-based measurements. Significant discrepancies were found, with the inventory-based emissions methodology resulting in a systematic 42% under-estimation of CFC-12 emissions from older refrigeration equipment and older vehicles, and a systematic 114% overestimation of emissions for HFC-134a, a refrigerant substitute for phased-out CFCs. Initial, inventory-based estimates for all F-gas emissions had assumed that equipment is no longer in service once it reaches its average lifetime of use. Revised emission estimates using improved models for equipment age at end-of-life, inventories, and leak rates specific to California resulted in F-gas emissions estimates in closer agreement to ambient-based measurements. The discrepancies between inventory-based estimates and ambient-based measurements were reduced from -42% to -6% for CFC-12, and from +114% to +9% for HFC-134a.
authors: California Air Resources Board, 1001 I Street, Sacramento, California 95814, United States.
authors: Glenn
authors: G
authors: Gallagher
authors: Tao
authors: T
authors: Zhan
authors: Ying-Kuang
authors: YK
authors: Hsu
authors: Pamela
authors: P
authors: Gupta
authors: James
authors: J
authors: Pederson
authors: Bart
authors: B
authors: Croes
authors: Donald R
authors: DR
authors: Blake
authors: Barbara
authors: B
authors: Barletta
authors: Simone
authors: S
authors: Meinardi
authors: Paul
authors: P
authors: Ashford
authors: Arnie
authors: A
authors: Vetter
authors: Sabine
authors: S
authors: Saba
authors: Rayan
authors: R
authors: Slim
authors: Lionel
authors: L
authors: Palandre
authors: Denis
authors: D
authors: Clodic
authors: Pamela
authors: P
authors: Mathis
authors: Mark
authors: M
authors: Wagner
authors: Julia
authors: J
authors: Forgie
authors: Harry
authors: H
authors: Dwyer
authors: Katy
authors: K
authors: Wolf
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002140:California; D005740:Gases / Q000032:analysis*; D057232:Global Warming; D054879:Halogenation
chemical_list: D000393:Air Pollutants; D005740:Gases