利用差分吸收光谱(DOAS)技术于2007年夏季对北京市朝阳区大气重要污染物O₃和NO₂进行了实时监测。分析了O₃、NO₂浓度的日变化规律，O₃呈现明显的日变化趋势，日间因光化学作用浓度高，且在午后出现最大值；夜间浓度低，日出前出现最低值。NO₂表现出与O₃相反的变化趋势，白天因光解浓度较低；夜间因交通排放和NO₂浓度积累达到峰值。观测结果与传统点式仪器进行了比较，对比结果显示两种方法有着很好的一致性。通过敏感性分析计算，表明O₃光化学生成处于挥发性有机化合物(VOCs)敏感。

Based on the differential optical absorption spectroscopy(DOAS) technology, in situ measurement of O₃ and NO₂ was carried out in Chaoyang District of Beijing in summer, 2007. Their diurnal variation characteristics are analyzed. O₃ showed a strong diurnal variation. Due to photochemical reaction, concentration of O₃ is high in day, and the maximum concentration occurs in the afternoon. Its concentration is low at night and the minimum value occurs before sunrise. The contrary trend is observed for NO₂. The concentration of NO₂ exhibits a diurnal variation with low level during daytime for photochemical reaction and high values during the night for traffic emissions. Measurement results are compared with the DOAS system and traditional point monitoring instruments, and good correlation is showed. Based on the sensitivity analysis, it can be found that O₃ production is sensitive to the VOCs.