Tian Zhi-Lin, Yang Wen-da, Yu Xiao-Fang, Zhang Man-Man, Zhang He-Wei, Cheng Ding, Cheng Peng, Wang Bo-Guang
Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China.
Huan Jing Ke Xue. 2018 May 8;39(5):2000-2009. doi: 10.13227/j.hjkx.201709269.
Nitrous acid (HONO) plays an important role in atmospheric photochemistry processes because its photolysis provides an efficient source of hydroxyl (OH) radicals in the troposphere. However, few studies exist on HONO in nocturnal chemistry processes. Using the observation data of HONO and related parameters for a super site at Guangzhou Jinan University in October 2015, the pollution processes and sources of HONO during nighttime were analyzed in this study. The results showed that the average concentration of HONO was 4.32 μg ·m during the nighttime, which was 2.6 times its concentration of 1.67 μg ·m in the daytime. The conversion rate of HONO, , during the nighttime was 0.0068 h, and the average contribution of vehicle emissions to HONO was 15.1%, with a peak of 37.8% at 20:00. The average net HONO generation rate from the reaction of NO and OH radicals during the night was 0.44 μg ·(m ·h). Correlation analysis suggested that particles could not be the major HONO source, but that relative humidity (RH; 33%-78%) was a key factor. Relevant calculation indicated that the heterogeneous reaction of deposited NO on humid ground surfaces could be the main source of HONO during nighttime.
亚硝酸（HONO）在大气光化学过程中起着重要作用，因为其光解为对流层中的羟基（OH）自由基提供了一个有效的来源。然而，关于HONO在夜间化学过程中的研究很少。本研究利用2015年10月广州暨南大学一个超级站点的HONO及相关参数的观测数据，分析了夜间HONO的污染过程和来源。结果表明，夜间HONO的平均浓度为4.32μg·m，是白天浓度1.67μg·m的2.6倍。夜间HONO的转化率为0.0068 h，车辆排放对HONO的平均贡献率为15.1%，20:00时峰值为37.8%。夜间NO与OH自由基反应产生HONO的平均净生成速率为0.44μg·(m·h)。相关性分析表明，颗粒物不是HONO的主要来源，而相对湿度（RH；33%-78%）是一个关键因素。相关计算表明，沉积在潮湿地面上的NO的非均相反应可能是夜间HONO的主要来源。
