选取2007年7月1日—8月31日中的21个晴空日,利用观测资料和光化学箱模式计算了北京城区测点的O3生成速率G(O3)和O3生成效率OPE.结果表明,21个晴空日中G(O3)日最高小时值分布在(18~82)×10-9h-1之间;在O3污染和非污染日G(O3)最高值的平均水平无显著差异,且与Ox浓度之间不存在一致的对应关系,表明O3化学生成过程不能全面解释地面O3浓度的累积,物理传输过程对测点O3实测浓度有显著作用;各个化学过程对G(O3)的贡献率对比结果显示,HO2在NO向NO2的转化中贡献最大;OPE值分布在2.8~5.8之间,总体水平为4.1±0.1;OPE值与NOx浓度之间为非线性关系,OPE值随NOx浓度的增加而减少,表明消减测点附近VOCs排放能有效降低O3浓度.
The gross ozone production rate G(Os ) and ozone production efficiency (OPE) is calculated with a photochemical box model constrained by observed data of 21 selected clear days obtained during July 1st to August 31th , 2004 in an urban area of Beijing. Results show that the daily maximum hourly -averaged G( O3 ) in these 21 selected clear days ranged from 18 ×10^-9 to 82 ×10^-9 h^-1. In average, the daily maximum G( O3 ) for ozone pollution days is not evidently different from that for ozone pollution-free days, and the G ( O3 ) is not in accord with the change of O3, either. This indicates that O3 photochemical production process could not explain the observed accumulation of O3 completely and physical transportation processes controlled the real O3 concentrations prominently. By comparing the contributions of individual chemical processes to the G( O3 ), it is shown that HO2 plays a dominant role in the conversion of NO to NO2. Ozone OPE ranged from 2.8 to 5.8, with art overall average of 4.1 ±0. 1 The relationship of OPE and NO, concentration is found to be non-linear and OPE decreases with increasing NOx , which indicates that reducing the exhaust of VOCs can drop O3 concentration efficiently in the observation area.