深圳市冬季大气中硝酸分配特征观测研究  

Observation of partitioning characteristics of gaseous nitric acid in winter of Shenzhen

作　　者：罗遥 林晓玉 牛英博 云龙 古添发 林楚雄 黄晓锋 何凌燕 LUO Yao;LIN Xiao-yu;NIUYing-bo;YUN Long;GU Tian-fa;LIN Chu-xiong;HUANG Xiao-feng;HE Ling-yan(Laboratory of Atmospheric Observation Supersite,School of Environment and Energy,Peking University Shenzhen Graduate School,Shenzhen 518055,China;Shenzhen Environmental Monitoring Center of Guangdong Province,Shenzhen 518049,China)

机构地区：[1]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 [2]广东省深圳生态环境监测中心站,广东深圳518049

出　　处：《中国环境科学》2023年第8期3877-3885,共9页China Environmental Science

基　　金：深圳市科技计划项目(GXWD20201231165807007-20200808165742001)。

摘　　要：总硝酸(TNO_(3)=HNO_(3)+NO_(3)^(-))的颗粒相分数ε(NO_(3)-)决定了TNO_(3)在大气中的寿命,然而在冬季城市地区对该分配过程仍然掌握较少.本研究于2022年1月1日~1月31日分别在深圳市城区点位和路边点位对大气HNO_(3)、NO_(3)-和相关污染物进行了在线连续观测.结果显示,深圳市城区冬季PM_(2.5)中NO_(3)-的平均浓度为(6.3±3.9)μg/m^(3),占PM_(2.5)质量浓度的24.7%,是PM_(2.5)中最重要的成分之一.本次观测期间城区点位和路边点位ε(NO_(3)^(-))均值分别为(0.81±0.13)和(0.75±0.16),TNO_(3)以向颗粒态分配为主.ε(NO_(3)^(-))日变化特征均表现为白天相对较低,夜间较高,较高的温度、较低的湿度和较酸性的环境会增强硝酸盐的挥发并向气相分配,从而驱动ε(NO_(3)^(-))的日变化.此外,气溶胶液态水含量(ALWC)和气溶胶pH值是影响深圳市冬季两个点位ε(NO_(3)_(-))差异性的最重要因素,平均贡献率分别为41%和31%,在对大气硝酸的生成转化进行模式模拟时这两个因素需被重点考虑.The particle phase fraction of total nitrate determines its lifetime in the atmosphere,but this distribution process in urban areas in winter remain poorly understood.In this study,concentrations of HNO_(3),NO_(3)^(-)and related pollutants was online observed at two sites(urban site and roadside site)in Shenzhen from January 1to January 31,2022.During the observation period,the average concentration of NO_(3)^(-)was(6.3±3.9)μg/m^(3),accounting for 24.7% of the mass concentration of PM_(2.5),which is one of the most important components of PM_(2.5) in winter in Shenzhen.The mean values ofε(NO_(3)^(-))at two sites were(0.81±0.13)and(0.75±0.16),respectively,and the distribution of nitrate was mainly to the particle phase.ε(NO_(3)^(-))reflected the gas-particle partitioning of nitrate,and it was higher during nighttime and lower during daytime.The higher temperature,lower humidity and more acidic environment would enhance nitrate volatilization and its partitioning to gas phase,thus driving the diurnal variation ofε(NO_(3)^(-)).In addition,aerosol liquid water content and aerosol pH were the most important factors affecting the difference of two-siteε(NO_(3)^(-))in winter of Shenzhen,with average contribution of 41% and 31%,respectively,indicating that these two factors should be taken into consideration when modeling the formation and transformation of gaseous nitric acid.

关 键 词：硝酸 硝酸盐 气溶胶pH值 气溶胶液态水含量 气粒分配 

分 类 号：X513[环境科学与工程—环境工程]