河北廊坊市区大气中NO、NO_2和O_3污染特征研究

Analysis of pollution characteristics of NO, NO_2 and O_3 at urban area of Langfang, Hebei

对廊坊市区为期3a(2013年1月~2015年12月)4个监测站点的NO、NO_2、NO_x和O_3浓度和气象要素进行了逐时连续观测.在此期间,廊坊市大气环境中的NO、NO_2、NO_x和O_3的平均浓度(×10^(-9))分别为15.10、23.00、38.10、23.25.结果显示:NO平均浓度最大值出现在07:00~09:00左右,与机动车排放增强和混合层高度较低有关;O_3呈现单峰分布并在15:00~16:00之间达到峰值;廊坊市臭氧周末效应可能原因是周末道路交通NO_x排放高峰比工作日排放大约晚2h,更有效地促进臭氧的生成.廊坊环境大气NO_x浓度与交通排放分别存在大约2~3h的滞后效应.春夏秋冬四季的NO_2平均光解速率(min^(-1))依次为:0.128、0.398、0.315、0.117,并在14:00~16:00达到峰值,NO-NO_2和O_3分别为NO_x的二次多项式、反比例函数.京津冀中小城镇NO_x浓度主要与局地污染物的输送和扩散有关,OX(NO_2+O_3)浓度受北京、天津等大都市区域传输影响突出,区域源贡献最高发生在16:00~18:00.

Continuous measurements were undertaken of NO, NO_2, O_3 and meteorological conditions at four monitoring stations at urban area of Langfang, Hebei province from January 2013 to December 2015. During this period, the mean concentrations（×10-（-9）） of NO, NO_2, NO_x and O_3 were 15.10, 23.00, 38.10 and 23.25 respectively. Peak NO concentrations often appear at about 07：00-09：00 in the morning due to increase in traffic emissions and reduction in boundary layer heights. O_3 show a single peak at about 15：00-16：00. The mean NO_2 photolysis rates（min-（-1）） reach top at 14：00-16：00 and vary with seasons which are 0.128 in spring, 0.398 in summer, 0.315 in autumn and 0.117 in winter. NO-NO_2, O_3 were fitted well as quadratic polynomial, inverse proportional function of NO_x respectively. NO_x and OX concentration of mid-small towns from Jing-Jin-Ji regions were differently affected by local, regional source contribution respectively. The peak regional contribution occurs at 16：00-18：00.