重庆市主城区大气水溶性离子在线观测分析

摘要

2015年12月-2016年3月期间,利用在线气体与气溶胶成分监测仪(IGAC)在重庆市大气超级站开展连续观测分析,并捕捉到2次持续时间较长的空气重污染过程.对PM2.5中9种水溶性离子及5种气态前体物的观测结果分析表明:NO3-、NH4+和SO2-是重庆市主城区PM2.5中主要的水溶性离子成分,其浓度均表现出明显的日变化特征,主要以(NH4)2SO4和NH4NO3的形式存在.NH3和SO2是最主要的气态污染物.2次重污染过程的水溶性离子组分有明显差异,细颗粒物累积型污染的NH4+、SO42-、NO3-浓度高,二次转化十分明显;春节期间烟花爆竹集中燃放,Cl-、K+浓度高,主要属于一次排放;污染期间主要离子组分的同源性特征显著.%Continuous detection of water-soluble ions was conducted from Dec,2015 to Mar,2016,using online gas and aerosol monitoring chromatography at Chongqing atmospheric supersite,and two long-lasting heavy pollution processes were caught.Nigh kinds of water-solubleions and five kinds of gaseous pollutant in PM2.5 were monitored.Results showed that NO3-,NH4+ and SO42-were major water-soluble ions in Chongqing urban area,which demonstrated obvious daily variation characteristics,and existed in forms of ammonium sulfates and ammonium nitrates.Ammonia and sulfur dioxide were dominant gaseous pollutants.During two pollution processes,the ionic components varied apparently.The content of NH4+,SO42-and NO3-was high when pollution was caused by accumulated fine particulate matter and secondary conversion was clear.The content of Cl-and K + from initial emission sources was high during spring festival due to burning of fireworks and crackers.Both pollution processes indicated that major detected water-soluble ions came from the same sources.