富氨地区秋冬季不同PM_(2.5)污染级别气溶胶酸性及其影响因素  

Aerosol acidity and its influencing factors at different PM_(2.5) pollution levels in ammonia-rich area in autumn and winter

作　　者：陈莹[1] 徐瑞欣 郝祺 姜楠[2] 刘洋[2] 张瑞芹[2] 陈静 CHEN Ying;XU Rui-xin;HAO Qi;JIANG Nan;LIU Yang;ZHANG Rui-qin;CHEN Jing(College of Chemistry,Zhengzhou University,Zhengzhou 450001,China;School of Ecology and Environment,Zhengzhou University,Zhengzhou 450001,China;Henan Environmental Monitoring Center,Zhengzhou 450004,China)

机构地区：[1]郑州大学化学学院,河南郑州450001 [2]郑州大学生态与环境学院,河南郑州450001 [3]河南省环境监测中心,河南郑州450004

出　　处：《中国环境科学》2022年第1期43-51,共9页China Environmental Science

基　　金：国家自然科学基金资助项目(52170117);河南省重点研发与推广专项(212102310065);国家重点研发计划(2017YFC0212403)。

摘　　要：为研究富氨地区秋冬季不同PM_(2.5)污染级别气溶胶酸性及其影响因素,于2018年10月15日~2019年2月28日,选择郑州市2个非城区点位——新密和航空港进行PM_(2.5)膜样本采集,采用离子色谱法测定其水溶性离子,通过ISORROPIA-Ⅱ模型计算气溶胶pH值,并分不同污染等级探讨PM_(2.5)主要离子浓度和pH值范围.结果显示:采样期间NO_(3)^(-)、NH_(4)^(+)和SO_(4)^(2-)是3种最主要的离子,随着污染程度的加剧,NO_(3)^(-)、SO_(4)^(2-)、NH_(4)^(+)呈现上升趋势,其中NO_(3)^(-)和NH_(4)^(+)的增长速度较大;NH_(4)^(+)/SO_(4)^(2-)的比值大于0.75,大气处于富氨条件,NH_(4)^(+)主要存在形式是(NH_(4))_(2)SO_(4)、NH_(4)NO_(3)、NH_(4)Cl;所选两点位PM_(2.5)的pH值呈中等酸性,新密4.6±0.6、航空港4.6±0.7,随着污染的加剧,pH值的变化范围逐渐收窄;敏感性分析表明影响秋冬PM_(2.5)的pH值变化的主要共同驱动因素是TNH_(3)(总氨(气体+气溶胶))、SO_(4)^(2-)和温度,随着污染的加剧,由TNH_(3)对气溶胶酸度的影响最大变为SO_(4)^(2-)对酸性的影响最大;随着pH值增大,总硝酸倾向于向颗粒态移动,总氨倾向于向气态移动,呈相反变化.This study was conducted to understand the aerosol acidity at different levels of air pollution and its influencing factors over ammonia-rich area in autumn and winter.Two non-urban sites in Zhengzhou,Xinmi and Airport,were selected for PM_(2.5) sample collection from 15th Oct 2018 to 28th Feb 2019.Ion chromatography was used for water-soluble inorganic ions.The aerosol model ISORROPIA-Ⅱ for pH values of PM_(2.5).The results show that NO_(3)^(-),NH_(4)^(+) and SO_(4)^(2-)were the three most important ions.With the worsening of the pollution,NO_(3)^(-),SO_(4)^(2-),NH_(4)^(+) showed an upward trend and both NO_(3)^(-) and NH_(4)^(+)increased at a greater rate.The ratio of NH_(4)^(+)/SO_(4)^(2-) higher than 0.75 implied that the atmosphere was in an ammonia-rich site.NH_(4)^(+)mainly existed in the form of(NH_(4))_(2)SO_(4),NH_(4)NO_(3) and NH_(4)Cl in autumn and winter.The PM_(2.5) pH was moderately acidic,4.6±0.6 at Xinmi and 4.6±0.7 at Airport,respectively.With the aggravation of pollution,the variation in pH value became smaller.TNH_(3),SO_(4)^(2-) and T were identified to be the main driving factors affecting the PM_(2.5) pH in winter and autumn.With the aggravation of pollution,the greatest factor manipulating aerosol acidity changed from TNH_(3) to SO_(4)^(2-).With an increase in pH values,TNO_(3) tended to become the particle phase,while TNH_(3) tended to be the gas phase.

关 键 词：富氨地区 ISORROPIA-Ⅱ模型 敏感性分析 重污染 气固分配 

分 类 号：X513[环境科学与工程—环境工程]