深圳市冬季夜间大气中N_(2)O_(5)污染特征  

The characterization of nocturnal dinitrogen pentoxide pollution in winter of Shenzhen

作　　者：云龙 牛英博 罗遥 陆骏铭 王均睿 林楚雄 古添发 邱志诚 黄晓锋 何凌燕 YUN Long;NIU Ying-bo;LUO Yao;LU Jun-ming;WANG Jun-rui;LIN Chu-xiong;GU Tian-fa;QIU Zhi-cheng;HUANG Xiao-feng;HE Ling-yan(Shenzhen Environmental Monitoring Center of Guangdong Province,Shenzhen 518049,China;Laboratory of Atmospheric Observation Supersite,School of Environment and Energy,Peking University Shenzhen Graduate School,Shenzhen 518055,China)

机构地区：[1]广东省深圳生态环境监测中心站,广东深圳518049 [2]北京大学深圳研究生院环境与能源学院大气观测超级站实验室,广东深圳518055

出　　处：《中国环境科学》2022年第12期5506-5513,共8页China Environmental Science

基　　金：国家重点研发计划项目(2018YFC0213901);深圳市科技计划项目(GXWD20201231165807007-20200808165742001)。

摘　　要：于2022年1月2~17日在深圳进行了为期15d的观测,基于化学电离飞行时间质谱仪器(ToF-CIMS)对气态N_(2)O_(5)和HNO_(3)进行了现场测量.冬季N_(2)O_(5)的夜间平均浓度为(174.3±262.0)×10^(-12),最高可达到4535.1×10^(-12).较高的N_(2)O_(5)反应活性表明夜间化学活动活跃,τ(N_(2)O_(5))^(-1)平均值在8.3×10^(-2)s^(-1),通过N_(2)O_(5)非均相水解反应形成的硝酸盐潜力大.通过对NO、NO_(2)、O_(3)和pNO_(3)^(-)的同步测量,量化表征了深圳市冬季夜间活性氮的化学行为;此外,通过奇数氧的收支分析发现,夜间HNO_(3)和pNO_(3)^(-)占据了O_(x)的主要成分且当(HNO_(3)+pNO_(3)^(-))系数为1.5时收支闭合,这表明N_(2)O_(5)的非均相水解是冬季夜间O_(x)去除的关键机制.The heterogeneous hydrolysis of N_(2)O_(5) has a significant impact on nocturnal particulate nitrate formation,yet this process in highly polluted urban areas in winter remain poorly understood.Previous N_(2)O_(5) observations in the Pearl River Delta are mainly concentrated in summer or warm conditions.At present,there is no report on the observation of N_(2)O_(5) at night in winter in Shenzhen.Here we presented measurements of gas-phase N_(2)O_(5) and HNO_(3) by high-resolution time-of-flight chemical ionization mass spectrometer(ToF-CIMS)during winter in urban ShenZhen,China.In this season,N_(2)O_(5) showed large day-to-day variations with average mixing ratios of(174.3±262.0)×10^(-12),with the maximum value of 4535.1×10^(-12).High reactivity of N_(2)O_(5),with averageτ(N_(2)O_(5))^(-1) of 8.3×10^(-2)s^(-1),suggested active nocturnal chemistry and a large nocturnal nitrate formation potential via N_(2)O_(5) heterogeneous uptake.Coupled with simultaneous measurement of NO,NO_(2),O_(3) and pNO_(3)^(-),the chemical behavior of active nitrogen in winter night of Shenzhen was quantitatively characterized.In addition,the analysis of odd oxygen budget showed that the measured concentrations of O_(3),NO_(2),HNO_(3) and pNO_(3)^(-) account for all of the O_(x),the O_(x) budget closure occurs at a ratio of 1.5(HNO_(3)+pNO_(3)^(-))formed per O_(x) lost,indicating N_(2)O_(5) hydrolysis as the mechanism in winter.

关 键 词：五氧化二氮 氮氧化物 夜间化学反应 奇数氧 

分 类 号：X511[环境科学与工程—环境工程]