Abstract
Abstract. Atmospheric hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) were measured in-situ at the Shangdianzi (SDZ) Global Atmosphere Watch (GAW) regional background station, China, from May 2010 to May 2011. The time series for five HFCs and three PFCs showed occasionally high-concentration events while background conditions occurred for 36% (HFC-32) to 83% (PFC-218) of all measurements. The mean mixing ratios during background conditions were 24.5 ppt (parts per trillion, 10−12, molar) for HFC-23, 5.86 ppt for HFC-32, 9.97 ppt for HFC-125, 66.0 ppt for HFC-134a, 9.77 ppt for HFC-152a, 79.1 ppt for CF4, 4.22 ppt for PFC-116, and 0.56 ppt for PFC-218. The background mixing ratios for the compounds at SDZ are consistent with those obtained at mid to high latitude sites in the Northern Hemisphere. North-easterly winds were associated with negative contributions to atmospheric HFC and PFC loadings (mixing ratio anomalies weighted by time associated with winds in a given sector), whereas south-westerly advection (urban sector) showed positive loadings. Chinese emissions estimated by a tracer ratio method using carbon monoxide as tracer were 3.6 ± 3.2 kt yr−1 for HFC-23, 4.3 ± 3.6 kt yr−1 for HFC-32, 2.7 ± 2.3 kt yr−1 for HFC-125, 6.0 ± 5.6 kt yr−1 for HFC-134a, 2.0 ± 1.8 kt yr−1 for HFC-152a, 2.4 ± 2.1 kt yr−1 for CF4, 0.27 ± 0.26 kt yr−1 for PFC-116, and 0.061 ± 0.095 kt yr−1 for PFC-218. The lower HFC-23 emissions compared to earlier studies may be a result of the HFC-23 abatement measures taken as part of Clean Development Mechanism (CDM) projects that started in 2005.
Highlights
Hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are greenhouse gases with global-warming potential (GWP) values for time horizon of 100 yr ranging from 140 to 11 700 (IPCC, 2007) and they are included in the Kyoto Protocol
We report the first in-situ measurement of HFC-23, HFC-32 (CH2F2), HFC-134a (CH2FCF3), Published by Copernicus Publications on behalf of the European Geosciences Union
One-year time series for HFC and PFC mixing ratios from 6 May 2010 to 5 May 2011 are shown in Fig. 4
Summary
Hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are greenhouse gases with global-warming potential (GWP) values for time horizon of 100 yr ranging from 140 to 11 700 (IPCC, 2007) and they are included in the Kyoto Protocol. HFC and PFC emissions are expected to have been increased in China within the last years in accordance with the high industrialization and from the substitutions of CFCs and HCFCs. Some Chinese emissions have been previously estimated based on measurements at stations downwind of China (Li et al, 2011; Kim et al, 2010; Saito et al, 2010; Stohl et al, 2010; Yokouchi et al, 2006). Only few atmospheric HFC and PFC measurements were made in China, mainly from air collected in canisters during campaigns (Barletta et al, 2006; Chan et al, 2006; Chan and Chu, 2007). HFC-152a (CH3CHF2), HFC-125 (CHF2CF3), CF4, PFC116 (C2F6), and PFC-218 (C3F8) at the World Meteorological Organization/Global Atmosphere Watch (WMO/GAW)’s regional background station Shangdianzi (SDZ) in northern China from May 2010 to May 2011. Chinese HFC and PFC emissions are estimated by a tracer ratio method using carbon monoxide as a reference tracer
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