title: [In-situ measurement of atmospheric methyl chloroform at the Shangdianzi GAW regional background station].
abstract: An in-situ GC-ECD monitoring system was established at the Shangdianzi GAW regional background station (SDZ) for a 2-year atmospheric methyl chloroform (CH3CCl3) measurement experiment. Robust extraction of baseline signal filter was applied to the CH3CCl3 time series to separate the background and pollution data. The yearly averaged background mixing ratios of atmospheric CH3CCl3 were (9.03 +/- 0.53) x 10(-12) mol x mol(-1) in 2009 and (7.73 +/- 0.47) x 10(-12) in 2010, and the percentages of the background data in the whole data were 61.1% in 2009 and 60.4% in 2010, respectively. The yearly background CH3CCl3 mixing ratios at SDZ were consistent with the northern hemisphere background levels observed at Mace Head and Trinidad Head stations, but lower than the results observed at sites in southern China and some Chinese cities from 2001 to 2005. During the study period, background mixing ratios trends exhibited a decreasing rate of 1.39 x 10 12(-12) a(-1). The wind direction with the maximum CH3CCl3 mixing ratio was from the southwest sector and that with the minimum ratio was from the northeast sector. The differences between the maximum and the minimum average mixing ratios in the 16 wind directions were 0.77 x 10(-12) (2009) and 0.52 x 10(-12) (2010). In the 16 different wind directions, the averaged mixing ratio of CH3CCl3 in 2010 was lower than that in 2009 by 1.03 x 10(-12) -1.68 x 10(-12).
authors.forename: Bo
authors.initials: B
authors.lastname: Yao
authors.forename: Ling-Xi
authors.initials: LX
authors.lastname: Zhou
authors.forename: Zhao
authors.initials: Z
authors.lastname: Liu
authors.forename: Gen
authors.initials: G
authors.lastname: Zhang
authors.forename: Ling-Jun
authors.initials: LJ
authors.lastname: Xia
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000032:analysis; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D014240:Trichloroethanes / Q000737:chemistry*; D014919:Wind
chemical_list: D000393:Air Pollutants; D014240:Trichloroethanes; C024566:1,1,1-trichloroethane