太原市城区冬季二次硝酸盐主导下PM_(2.5)的形成及防控  

Formation and Control of PM_(2.5) Dominated by Secondary Nitrate in Winter in Taiyuan Urban Area

作　　者：冯凯琛 崔阳 樊洁 李亚楠 何秋生[1] 郭利利 李宏艳 FENG Kai-chen;CUI Yang;FAN Jie;LI Ya-nan;HE Qiu-sheng;GUO Li-li;LI Hong-yan(School of Environmental Science and Engineering,Taiyuan university of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学环境与资源学院,太原030024

出　　处：《太原科技大学学报》2025年第1期88-93,共6页Journal of Taiyuan University of Science and Technology

基　　金：国家自然科学基金(42077201);国家生态环境部攻关项目(DQGG202107);太原科技大学博士启动基金(20202072,20222071)。

摘　　要：二次硝酸盐是PM_(2.5)中的重要二次无机离子组分,为了研究我国北方典型工业城市二次硝酸盐主导下PM_(2.5)的形成及防控途径,基于太原市城区点位2021~2022年高时间分辨率的PM_(2.5)在线监测数据,对气溶胶颗粒物的离子组分及气态前体物进行了研究分析。结果表明,太原冬季PM_(2.5)平均浓度为63.5μg/m^(3),主要离子组分为NO_(3)^(-)、NH_(4)^(+)和SO_(4)^(2-)在PM_(2.5)中的占比分别为16.2%、11.2%和10.9%.在污染日和清洁日,硝酸盐对水溶性无机离子的贡献分别达到32.1%和37.2%,为驱动冬季PM_(2.5)升高的首要组分。硝酸盐受温度变化影响较小,在冬季14∶00~17∶00的日间峰值主要源于光化学反应生成大量的HNO_(3),并在富氨条件下与NH_(3)的中和反应。通过使用ISORROPIA-II热力学模型计算气溶胶液态水(ALWC)含量和pH值,对控制NH_(4)NO_(3)形成的前体进行敏感性分析。结果显示,太原市NH_(4)NO_(3)的形成主要处于HNO_(3)敏感区域,因此通过控制HNO_(3)的前体物NOx或者减弱大气氧化性干扰HNO_(3)的形成可以有效抑制NH_(4)NO_(3)的形成。特别是在湿度较高的时段,对HNO_(3)和NH_(3)开展协同控制可以更加有效地减少NH_(4)NO_(3)的形成。Secondary nitrate was an important component of inorganic ions in PM_(2.5).In order to investigate the formation and control measures of PM_(2.5) dominated by secondary nitrate in typical industrial cities in northern China,the ion composition and gaseous precursors of aerosol particles were studied based on high time-resolution online monitoring data of PM_(2.5) at urban sites in Taiyuan from 2021 to 2022.The results showed that the average concentration of PM_(2.5) in Taiyuan in winter was 63.5μg/m^(3),with the main ion components being NO_(3)^(-),NH_(4)^(+),and SO_(4)^(2-),accounting for 16.2%,11.2%and 10.9%of PM_(2.5),respectively.On polluted and clean days,the contribution of nitrate to water-soluble inorganic ions reached 32.1%and 37.2%,respectively,making it the primary component driving the increase of winter PM_(2.5).Nitrate was less affected by temperature,and the daytime peak from 14∶00 to 17∶00 in winter was mainly due to the photolytic production of a large amount of HNO_(3),which neutralized with NH_(3) under ammonia-rich conditions.Sensitivity analysis of the precursors controlling NH_(4)NO_(3) formation was performed by using the ISORROPIA-II thermodynamic model to calculate the liquid water content(ALWC)and pH of aerosol particles.The results showed that the formation of NH_(4)NO_(3) in Taiyuan was mainly in the HNO_(3) sensitive area,and therefore controlling the precursor NOx of HNO_(3) or reducing atmospheric oxidative interference with the formation of HNO_(3) could effectively inhibit the formation of NH_(4)NO_(3).Especially during periods of high humidity,coordinated control of HNO_(3) and NH_(3) could more effectively reduce the formation of NH_(4)NO_(3).

关 键 词：PM_(2.5) 硝酸盐 NH_(3) HNO_(3) 敏感性分析 

分 类 号：X513[环境科学与工程—环境工程]