In-situ measurements of atmospheric hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) at the Shangdianzi regional background station, China

摘要

Atmospheric hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) weremeasured in-situ at the Shangdianzi (SDZ) Global Atmosphere Watch (GAW) regionalbackground station, China, from May 2010 to May 2011. The time series forfive HFCs and three PFCs showed occasionally high-concentration events whilebackground conditions occurred for 36% (HFC-32) to 83% (PFC-218) ofall measurements. The mean mixing ratios during background conditions were24.5 ppt (parts per trillion, 10, molar) for HFC-23, 5.86 ppt forHFC-32, 9.97 ppt for HFC-125, 66.0 ppt for HFC-134a, 9.77 ppt for HFC-152a,79.1 ppt for CF, 4.22 ppt for PFC-116, and 0.56 ppt for PFC-218. Thebackground mixing ratios for the compounds at SDZ are consistent with thoseobtained at mid to high latitude sites in the Northern Hemisphere.North-easterly winds were associated with negative contributions toatmospheric HFC and PFC loadings (mixing ratio anomalies weighted by timeassociated with winds in a given sector), whereas south-westerly advection(urban sector) showed positive loadings. Chinese emissions estimated by atracer ratio method using carbon monoxide as tracer were 3.6 ± 3.2 kt yrfor HFC-23, 4.3 ± 3.6 kt yr for HFC-32, 2.7 ± 2.3 kt yrfor HFC-125, 6.0 ± 5.6 kt yr for HFC-134a,2.0 ± 1.8 kt yr for HFC-152a, 2.4 ± 2.1 kt yr forCF, 0.27 ± 0.26 kt yr for PFC-116, and 0.061 ± 0.095 kt yrfor PFC-218. The lower HFC-23 emissions compared to earlierstudies may be a result of the HFC-23 abatement measures taken as part ofClean Development Mechanism (CDM) projects that started in 2005.