上海浦东新区城区大气PM_(2.5)中水溶性离子污染特征研究  

Study on Pollution Characteristics of Water-soluble Ions in PM_(2.5) in Pudong New District

作　　者：黄敏 HUANG Min(Environmental Monitoring Station of Pudong New District,Shanghai 200135,China)

机构地区：[1]上海市浦东新区环境监测站,上海200135

出　　处：《环境监控与预警》2022年第2期70-77,共8页Environmental Monitoring and Forewarning

基　　金：上海市科委科技创新基金资助项目(19DZ1205007)。

摘　　要：为研究大气中细颗粒物(PM_(2.5))在中低浓度水平下的污染特征及来源,于2018—2020年在上海市浦东新区采用在线气体组分及气溶胶监测系统对大气ρ(PM_(2.5))及其水溶性离子的质量浓度进行了在线连续观测。结果表明,2018—2020年ρ(PM_(2.5))变化总体均呈现冬季较高,春、秋季其次,夏季较低的特征。PM_(2.5)中水溶性离子组分按质量浓度大小排序为:ρ(NO_(3)^(-))>ρ(SO_(4)^(2-))>ρ(NH_(4)^(+))>ρ(Cl^(-))>ρ(K^(+))>ρ(Na^(+)),SO_(4)^(2-)、NO_(3)^(-)和NH_(4)^(+)(SNA)占总离子浓度的94%以上,占PM_(2.5)的52%以上,是影响PM_(2.5)的重要组分。Cl^(-)约占3%,Na^(+)和K^(+)占比均<1%。NO_(3)^(-)离子浓度随季节变化程度最大。春季颗粒物明显表现为弱酸性,冬季颗粒物则呈现出向弱碱性发展的态势,全年总体基本呈中性。通过离子平衡计算,SNA在大气中主要倾向于以(NH_(4))_(2)SO_(4)和NH_(4)NO_(3)的形式存在。SO_(4)^(2-)、NO_(3)^(-)和NH_(4)^(+)相关性较高,Cl^(-)和K^(+)相关性较高,具有同源性。硫氧化率(SOR)与氮氧化率(NOR)均>0.1,SO_(2)和NO_(2)的二次转化程度较高。机动车尾气排放及其引起的二次粒子和区域输送已经成为观测期间内PM_(2.5)的主要来源。To study the characteristics and sources of the fine particulate matter(PM_(2.5))in the middle and lower levels of pollution in the atmosphere,an online monitoring system for atmospheric gas composition and aerosol were used to trackρ(PM_(2.5))and the concentration of the water-soluble ions in Pudong New District,from January 1,2018,to December 31,2020.The results showed thatρ(PM_(2.5))was the highest in winter,followed by in spring and in autumn,and it was the lowest in summer.The order of water-soluble ion components in PM_(2.5) by mass concentration was as follow:ρ(NO_(3)^(-))>ρ(SO_(4)^(2-))>ρ(NH_(4)^(+))>ρ(Cl^(-))>ρ(K^(+))>ρ(Na^(+)),while the sum concentration of SO_(4)^(2-),NO_(3)^(-),and NH_(4)^(+)(SNA)accounted for over 94%of the total ion components and over 52%of PM_(2.5),which were the key factors in PM_(2.5).The percentage of Cl^(-)was about 3%.The percentages of Na^(+)and K^(+)were both less than 1%.The concentration of NO_(3)^(-) changed the most with the season.In spring,the particulate matter was weakly acidic,while in winter,it developed to weakly alkaline,and that of the whole year was neutral.Based on ion equilibrium calculations,SNA tends to exist in the atmosphere primarily as(NH_(4))_(2)SO_(4) and NH_(4)NO_(3).SO_(4)^(2-),NO_(3)^(-) and NH_(4)^(+)had a high correlation,while Cl^(-)and K^(+)had a high correlation with homology.The sulfur oxidation rate(SOR)and nitrogen oxidation rate(NOR)were both higher than 0.1,and the secondary transformation degree of SO_(2) and NO_(2) was higher.Vehicles exhaust and the following secondary particles transmitting and regional transmitting had become the main source of fine particles in the observation period.

关 键 词：细颗粒物 水溶性离子 在线离子色谱 污染特征 

分 类 号：X513[环境科学与工程—环境工程]