title: [Study of the "weekend effect" of O3, NOx and other pollutants in summer of Beijing].
abstract: The data of O3, NOx (NO and NO2), CO and SO2 observed at Beijing 325m meteorological tower from June 25 to July 7, 2000 and from July 26 to August 22, 2000 are used to analyze the difference of pollutant concentrations on weekends and weekdays, and its causes. Results show that except SO2, the correlations of O3, NOx, NO, NO2 and CO concentrations between weekends and weekdays are very significant,since they all pass the t-test significance level at alpha = 0.05. The correlation coefficients (R) are 0.99, 0.61, 0.56, 0.80 and 0.61 for O3, NOx, NO, NO2 and CO3, respectively. Weekend NO, and CO concentrations are lower than weekday concentrations in rush hours (06:00-08:00), and the mean deviations for NOx and CO concentrations are -28% and -9%, respectively. The regression coefficient of O3 concentrations between weekends and weekdays is 1.25 +/- 0.02. Furthermore, the maximum 1-h average O3 concentration and maximum 8-h average O3 concentration on weekends are 23% and 26% higher than those on weekdays, respectively, indicating an obvious O3 "weekend effect".
authors.affiliation: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. shiyz@mail.iap.ac.cn
authors.forename: Yu-zhen
authors.initials: YZ
authors.lastname: Shi
authors.forename: Yong-fu
authors.initials: YF
authors.lastname: Xu
authors.forename: Geng-chen
authors.initials: GC
authors.lastname: Wang
authors.forename: Li-qing
authors.initials: LQ
authors.lastname: Shi
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002947:Cities; D009569:Nitric Oxide / Q000032:analysis*; D009585:Nitrogen Dioxide / Q000032:analysis; D010083:Oxidants, Photochemical / Q000032:analysis; D010126:Ozone / Q000032:analysis*; D012621:Seasons; D013458:Sulfur Dioxide / Q000032:analysis; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D010083:Oxidants, Photochemical; D001335:Vehicle Emissions; D013458:Sulfur Dioxide; D009569:Nitric Oxide; D010126:Ozone; D009585:Nitrogen Dioxide