太原市城区冬季二次硝酸盐主导下PM2.5的形成及防控  

Formation and Control of PM 2.5 Dominated by SecondaryNitrate 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PM2.5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PM2.5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PM2.5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PM2.5平均浓度为63.5μg/m3,主要离子组分为NO3-、NH4+和SO42-在PM2.5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PM2.5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HNO3,并在富氨条件下与NH3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NH4NO3形成的前体进行敏感性分析。结果显示,太原市NH4NO3的形成主要处于HNO3敏感区域,因此通过控制HNO3的前体物NOx或者减弱大气氧化性干扰HNO3的形成可以有效抑制NH4NO3的形成。特别是在湿度较高的时段,对HNO3和NH3开展协同控制可以更加有效地减少NH4NO3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 2-4,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：PM2.5 硝酸盐 NH3 HNO3 敏感性分析 

分 类 号：X513[环境科学与工程—环境工程]