基于扫描长程差分吸收光谱(DOAS)系统于2007年8月27日～9月4日期间对北京市郊区进行了大气污染物HONO和NO2等垂直廓线的连续监测, 详细探讨了HONO, NO2和HONO/ NO2比值的垂直分布特征, 重点研究了HONO的形成途径。 结果显示HONO和NO2浓度随着高度的增加而降低, 而HONO浓度梯度下降的更加剧烈; HONO/NO2比值也随着高度的增加而降低, 表明在地面及近地面NO2与水汽的非均相反应是HONO的主要来源, HONO在近地面附近形成, 然后传输到上层空间。

Based on the scanning differential optical absorption spectroscopy (DOAS) system, field measurement of vertical profiles of HONO and NO2 was performed continuously from Aug.27, 2007 to Sep.4, 2007 in Chaoyang District of Beijing, and their vertical profiles were analyzed.Based on the acquired data, the typical vertical variation characteristics of HONO, NO2 and the ratio HONO/NO2 were discussed, and the possible formation sources of HONO were studied.The results indicated that the decrease of HONO with height was faster than the decrease of NO2.The study found good correlation between NO2 and HONO, as well as between the ratio HONO/NO2 and vapor, respectively.Therefore, the authors’ conclusion is that HONO was formed by heterogeneous conversion of NO2 on surfaces or near ground and then transported to higher altitudes.