摘要
基于大流量旋风式冲击采样器在西安市采集了四季大气PM2.5粉末样品,分别测定其水溶和非水溶相的氧化潜势(OP)、无机元素、水溶性离子,金属组分、碳组分和有机官能团,揭示水溶相/非水溶相的化学组分对OP的影响.结果显示,西安市PM25粉末样品总OP的趋势为秋冬(秋7.24μmol/(min·mg),冬 5.19μmol/(min·mg))显著高于春夏季(春 2.06μmol/(min·mg),夏 3.15μmol/(min·mg));春夏季 PM2.5 粉末样品的 OP 以水溶相 OP 为主(70.0％),秋冬季以非水溶相为主(73.9％).水溶性金属Ni、Pb、Ba、Mn、Cu、Ti(0.60＜R＜0.80,P＜0.05)和水溶性有机碳(TOC)(R=0.54,P＜0.05)与水溶相OP呈较显著的正相关.非水溶性金属(Cu、Fe、Cr等)与非水溶相OP普遍呈较显著的正相关(0.48＜R＜0.71,P＜0.05),非水溶性元素碳(EC)与非水溶相OP则呈显著负相关(-0.63＜R＜-0.45,P＜0.05).傅里叶红外光谱的结果显示,酚、醇、醚、酯等含氧水溶性有机物对PM25粉末样品中水溶相OP有重要的影响.
Abstract
Seasonal powder samples of PM2.5 in Xi'an City were collected in this study based on the large flow cyclone impact sampler.By measuring the oxidative potential(OP)of water-soluble and water-insoluble phases,as well as the inorganic elements,water-soluble ions,carbon components,and organic functional groups in PM2.5,the contribution of water-soluble/water-insoluble phases to OP were revealed and the impacts of chemical components on OP were discussed.The results showed that the total OP of PM2.5 in Xi'an was significantly higher in autumn and winter(7.24 and 5.19μmol/(min·mg)in autumn and winter,respectively)than in spring and summer(2.06 and 3.15μmol/(min·mg)in spring and summer,respectively).The OP of PM2.5 in spring and summer were mainly contributed by water-soluble phase(averagely 70.0％),instead of water-insoluble phase(averagely 73.9％)in autumn and winter.Water-soluble metals,especially heavy metals such as Ni,Pb,Ba,Mn,Cu and Ti,(0.60＜R＜0.80,P＜0.05)and the water-soluble organic carbon(TOC)(R=0.54,P＜0.05)showed strong correlations with water-soluble OP.Significant positive correlations between water-insoluble metals(Cu,Fe,Cr,etc.)and water-insoluble phase OP(0.48＜R＜0.71,P＜0.05)were observed,while a significant negative correlation was found between water-insoluble EC and water-insoluble OP(-0.63＜R＜-0.45,P＜0.05).The results of Fourier transform infrared spectroscopy showed that oxygenated water-soluble organics such as phenols,alcohols,ethers,esters,etc.,should be responsible for the high OP of PM2.5 samples.
基金项目
陕西省重点研发项目(2022ZDLSF06-07)
中国博士后自然科学基金资助项目(2021M692549)
中央高校基本科研业务费资助项目(xjh012020024)
万方数据