北京市夏季O_3、NO_x等污染物“周末效应”研究

Study of the "Weekend Effect" of O_3,NO_x and Other Pollutants in Summer of Beijing

采用了2000-06-25-2000-07-07以及2000-07-26-2000-08-22在北京325 m气象塔观测平台观测到的O3、NOx（NO和NO2）、CO和SO2数据,分析了周末与工作日O3、NOx、NO、NO2、CO和SO2浓度变化的差异及成因.结果表明,除SO2之外,O3、NOx、NO、NO2和CO的周末浓度与对应工作日浓度相关性显著,均通过了显著性水平α=0.05的t检验,相关系数（R）依次为0.99、0.61、0.56、0.80和0.61.交通高峰时段（06：00-08：00）NOx和CO的周末浓度明显低于工作日浓度,该时段NOx和CO的周末浓度与工作日浓度的平均偏差分别为-28%和-9%.O3周末浓度与工作日浓度的回归系数为1.25±0.02.此外,周末O3的最大小时浓度值与最大8 h平均浓度值分别比工作日高23%和26%,表现出十分明显的“周末效应”.

The data of 03, 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 03 , NO,, NO, NO2 and CO concentrations between weekends and weekdays are very significant,since they all pass the t-test significance level at a = 0.05. The correlation coefficients （R） are 0.99, 0.61, 0.56, 0.80 and 0.61 for 03, NOx, NO, NO2 and CO, respectively. Weekend NOx and CO concentrations are lower than weekday concentrations in rush hours （06：00 - 08：00）, and the mean deviations for NO, 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 03 concentration and maximum 8-h average 03 concentration on weekends are 23 % and 26 % higher than those on weekdays, respectively, indicating an obvious 03 ＂weekend effect＂ .