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Yao B.,Chinese Academy of Meteorological Sciences | Li P.-C.,Chinese Academy of Meteorological Sciences | Zhou L.-X.,Chinese Academy of Meteorological Sciences | Xu L.,Chinese Academy of Meteorological Sciences | And 4 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2012

Air samples were flushed and pumped into two-port stainless steel canisters and pressurized to 1.36×10 5 Pa by a custom-made sampler. The samplers were analyzed by a gas chromatography-mass spectrometry (GC-MS) system in the laboratory. The precisions of 6 major hydrofluorocarbons (HFCs) analysis were 0.24%~1.02%. The concentrations of 6 HFCs in the blank samples were below detection limits of GC-MS system. The influence caused by various inlet pressures fluctuation was corrected. The recoveries for 6 HFCs during sampling-analysis procedure were 99.5%~100.4% and there were not significant changes of the HFCs concentrations during 112-days storage. Air samples from the top of an 80-m tower at Shangdianzi regional station were sampled and analyzed. The concentration differences between two parallel samples were 0.04×10 -12~0.16×10 -12. The concentrations difference between canister samples and in-situ measurement were -0.17×10 -12~-0.86×10 -12. The sampling-analysis-quality control method was suitable for high precision atmospheric HFCs observation. Source


Yao B.,Chinese Academy of Meteorological Sciences | Zhou L.-X.,Chinese Academy of Meteorological Sciences | Zhang F.,Chinese Academy of Meteorological Sciences | Zhang X.-C.,Chinese Academy of Meteorological Sciences | And 5 more authors.
Huanjing Kexue/Environmental Science | Year: 2010

An in situ GC-ECD monitoring system was established at the Shangdianzi GAW Regional station from April 2007 to March 2008, and the mixing ratio of atmospheric HCFC-22 was (278.1±113.6)×10-12 (mol/mol). A "R" statistical software was applied to the HCFC-22 time series to separate background and pollution data. The background HCFC-22 mixing ratio was (199.5±5.1)×10-12, close to northern hemisphere background level observed at Mace Head and Trinidad Head stations. The pollution HCFC-22 mixing ratio was (312.1±121.0)×10-12 due to anthropogenic emission from various regions and air mass transport. There was no significant seasonal variability of background data. However, pollution data was much higher in summer than that in winter, and elevated up to 100.9×10-12 in July than in January attribute to seasonal emission characteristics. The mean HCFC-22 mixing ratio from southwest wind sector (327.3×10-12) was much higher than that of northeast sector (236.2×10-12). The W-WSW-SW wind sector has a positive contribution to the HCFC-22 level, while NNE-N-NE has a large negative contribution. Source


Zhang F.,Chinese Academy of Meteorological Sciences | Zhang F.,University of Chinese Academy of Sciences | Zhou L.X.,Chinese Academy of Meteorological Sciences | Yao B.,Chinese Academy of Meteorological Sciences | And 6 more authors.
Science China Earth Sciences | Year: 2011

An in-situ GC-ECD system was used to measure halocarbons at Shangdianzi (SDZ) GAW regional station. In this paper, we reported observational results of atmospheric CFC-11 (CCl3F) mixing ratios from April 2007 to March 2008. The CFC-11 time series showed large variability. Approximately 62% observed values were filtered as non-background data. The median, 10% and 90% percentiles of CFC-11 background mixing ratios were 245.4 ppt (10-12 mol/mol), 244.6 ppt and 246.1 ppt, respectively; whereas those of non-background CFC-11 mixing ratios were 254.7, 246.6 and 272.1 ppt, respectively. Significant differences in background and non-background CFC-11 mixing ratios were observed between summer and autumn, mainly because of the CFC-11 stored in foam being prone to atmospheric release in hot seasons. Comparison of the SDZ data with the five AGAGE stations suggested agreement with mid-high latitude Northern Hemisphere stations MHD, THD and RPB. The SDZ data were higher than that of Southern Hemisphere stations CGO and SMO. Higher CFC-11 mixing ratios measured in different seasons were always associated with winds from the W-WSW-SW sector, indicating that the airflow coming from this wind sector has a positive contribution to CFC-11concentrations. The CFC-11 mixing ratios were higher in autumn and summer than in spring and winter, in which its mixing ratios were very close to the atmospheric background level. This was happened especially when airflow originated from the NNE-NE-ENE-E sector, indicating the air masses coming from these wind directions was relatively clean. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg. Source


Yao B.,Chinese Academy of Meteorological Sciences | Zhou L.,Chinese Academy of Meteorological Sciences | Zhang F.,Chinese Academy of Meteorological Sciences | Xu L.,Chinese Academy of Meteorological Sciences | And 6 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2010

A gas chromatography-electron capture detector (GC-ECD) system was established at the Shangdianzi GAW (Global Atmosphere Watch) regional station for in-situ measurement of atmospheric carbon tetrachloride mixing ratios. From April 2007 to March 2008, the background CCl4 mixing ratio was (89.4 ± 0.7) × 10-12 mol · mol-1, close to the northern hemisphere background level observed at the Mace Head and the Trinidad Head stations. The polluted CCl4 mixing ratio was (94.7 ± 5.1) × 10-12 primarily due to anthropogenic emission from various regions and air mass transport. There was no significant seasonal variability of the background CCl4 data. However, the polluted data was much higher in summer than in winter, elevated up to 7.6 × 10-12. Good correlation was observed between the enhanced CCl4 and the enhanced CO mixing ratios. A CO tracer-ratio method was applied to estimate the CCl4 emission from China during the study period. The estimated CCl4 emission was 4.7 kt · a-1 using the CO tracer-ratio method, which was close to the literature result obtained by the bottom-up method. Uncertainty of the emission estimate comes mainly from the homologous source assumption and station representativeness. Source

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