Aug 25, 2010
Citations
3
Influential Citations
68
Citations
Journal
Atmospheric Chemistry and Physics
Abstract
HFC-23 (also known as CHF3, fluoroform or tri- fluoromethane) is a potent greenhouse gas (GHG), with a global warming potential (GWP) of 14 800 for a 100-year time horizon. It is an unavoidable by-product of HCFC- 22 (CHClF2, chlorodifluoromethane) production. HCFC- 22, an ozone depleting substance (ODS), is used extensively in commercial refrigeration and air conditioning, in the ex- truded polystyrene (XPS) foam industries (dispersive appli- cations) and also as a feedstock in fluoropolymer manufac- ture (a non-dispersive use). Aside from small markets in spe- cialty uses, HFC-23 has historically been considered a waste gas that was, and often still is, simply vented to the atmo- sphere. Efforts have been made in the past two decades to reduce HFC-23 emissions, including destruction (incinera- tion) in facilities in developing countries under the United Nations Framework Convention on Climate Change's (UN- FCCC) Clean Development Mechanism (CDM), and by pro- cess optimization and/or voluntary incineration by most pro- ducers in developed countries. We present observations of lower-tropospheric mole frac- tions of HFC-23 measured by "Medusa" GC/MSD in- struments from ambient air sampled in situ at the Ad- vanced Global Atmospheric Gases Experiment (AGAGE) network of five remote sites (2007-2009) and in Cape