长沙市冬季不同污染水平颗粒物中二次无机离子赋存形态及生成特征  

Occurrence Patterns and Generation Characteristics of Secondary Inorganic Ions in PM_(2.5) at Different Pollution Levels in Changsha City in Winter

作　　者：周国治 陶丽 龙薇 谢雨竹 Zhou Guozhi;Tao Li;Long Wei;Xie Yuzhu(Hunan Ecological Environment Monitoring Center,Changsha 410014,Hunan,China;Wuxi CAS Photonics Co.Ltd,Wuxi 214100,Jiangsu,China)

机构地区：[1]湖南省生态环境监测中心,湖南长沙410014 [2]无锡中科光电技术有限公司,江苏无锡214100

出　　处：《绿色科技》2024年第10期156-161,167,共7页Journal of Green Science and Technology

摘　　要：基于PM_(2.5)中二次无机离子(SNA)、气态前体物以及气象参数在线监测数据,对长沙冬季不同污染水平下SNA浓度、赋存形态及生成特征进行分析。结果显示,NO_(3)^(-)、NH_(4)^(+)和SO_(4)^(2-)浓度分别为(20.6±14.1)μg/m^(3) ,(7.0±3.9)μg/m^(3) 和(5.2±2.8)μg/m^(3) 。SNA同PM_(2.5)浓度的占比高达53.9%,组分中NO_(3)^(-)浓度贡献最大。污染天SNA浓度是清洁天的1.3倍,NO_(3)^(-)涨幅最大。相较于清洁天,污染天气态前体物NO_(2) 和SO_(2) 浓度及相对湿度较高。清洁天SNA主要以(NH_(4) )_(2) SO_(4) 和NH_(4) NO_(3) 的形式存在,而污染天SNA主要以NH_(4) HSO_(4) 和NH_(4) NO_(3) 的形式存在。长沙冬季气溶胶pH均值为3.1,污染天气溶胶pH值更低。污染天氮氧化率(NOR)和硫氧化率(SOR)均高于清洁天。污染天SOR、NOR与AWC的相关性也明显高于清洁天。污染天SO_(4)^(2-)生成以液相反应为主,NO_(3)^(-)生成以非均相反应为主,AWC的升高促进SOR和NOR。Based on the online monitoring data of secondary inorganic ions(SNA)in PM_(2.5),gaseous pollutants and the meteorological factors,this study analyzed the variation characteristics,occurrence patterns and generation characteristics of secondary inorganic ions in PM_(2.5) at different pollution levels.The results showed that the mean concentrations of NO_(3)^(-),SO_(4)^(2-) and NH_(4)^(+) were(20.6±14.1)μg/m^(3) ,(7.0±3.9)μg/m^(3) ,(5.2±2.8)μg/m^(3) ,respectively.SNA accounted for 53.9%of PM_(2.5) mass concentration,and NO_(3)^(-) was the main contributor.The concentrations of SNA on pollution days were 1.3 times higher than those on clean days,and NO_(3)^(-) increased the most.Compared to the clean days,NO_(2) ,SO_(2) and relative humidity are higher on pollution days.SNA existed primarily as(NH_(4) )_(2) SO_(4) and NH_(4) NO_(3) on clean days.However,SNA mainly existed in the form of(NH_(4) )HSO_(4) and NH_(4) NO_(3) on pollution days.The average pH of aerosol in Changsha was 3.1,with higher acidity observed on pollution days.The mean values of sulfur oxidation ratio(SOR)and nitrogen oxidation ratio(NOR)were higher on pollution days than on clean days.The correlation between SOR,NOR and AWC on pollution days was also significantly higher than on clean days.The generation of SO_(4)^(2-) was dominated by liquid-phase reaction,and the generation of NO_(3)^(-) was dominated by heterogeneous hydrolysis on pollution days.Overall,AWC promoted SOR and NOR.

关 键 词：PM_(2.5)污染 二次无机离子(SNA) 二次转化 气溶胶液态含水量(AWC) 

分 类 号：X51[环境科学与工程—环境工程]