石家庄秋季一次典型霾污染过程水溶性离子粒径分布特征  

Characteristics of the Size Distribution of Water Soluble Inorganic Ions During a Typical Haze Pollution in the Autumn in Shijiazhuang

作　　者：刘景云[1,2] 刘子锐[2] 温天雪[2] 虢俊龙 黄小娟[2] 乔宝文[1,2] 王莉莉[2] 杨洋[3] 徐仲均[1] 王跃思[2] 

机构地区：[1]北京化工大学环境科学与工程系,北京100029 [2]中国科学院大气物理研究所,大气边界层物理和大气化学国家重点实验室,北京100029 [3]河北省人工影响天气办公室,石家庄050800

出　　处：《环境科学》2016年第9期3258-3267,共10页Environmental Science

基　　金：中国科学院战略性先导科技专项(XDB05020000,XDA05100100);国家自然科学基金项目(41230642)

摘　　要：为研究石家庄秋季典型霾污染过程中颗粒物水溶性离子的粒径谱分布,并进一步分析其来源及形成机制,于2013年10月15日到11月14日利用惯性撞击式8级采样器(Andersen)对石家庄城区大气颗粒物进行了为期一个月的连续采样,并使用离子色谱仪对观测期间一次霾污染过程颗粒物中8种水溶性无机离子(Na^+、NH_4^+、K^+、Mg^(2+)、Ca^(2+)、Cl^-、NO_3^-、SO_4^(2-))进行了分析.结果表明,石家庄秋季颗粒物污染严重,采样期间PM10和PM2.5日均值分别达到(361.2±138.7)μg·m^(-3)和(175.6±87.2)μg·m-3,PM_(2.5)日均值达到国家环境空气质量二级标准的2.3倍.此次污染过程,优良天、轻/中度污染天和重度污染天总悬浮颗粒物中总水溶性无机离子(TWSII)浓度日均值分别为(64.4±4.6)、(109.9±22.0)和(212.9±50.1)μg·m-3,由优良天过渡到重度污染天,总水溶性无机离子中二次无机离子(SO_4^(2-)、NO_3^-和NH_4^+)的比例由44.9%上升至77.6%,此次的霾污染过程主要来源于二次无机离子的生成和积累.优良天,SO_4^(2-)、NO_3^-和NH_4^+呈现双模态分布,峰值分别出现在0.43~0.65μm和4.7~5.8μm,而在轻/中度污染天和重度污染天,逐渐转变为单模态分布,峰值出现在0.65~1.1μm,随着高湿度下液相反应的加剧,二次无机离子由凝结模态向液滴模态转移的迹象明显.Na+、Mg^(2+)和Ca^(2+)这3种离子在优良天、轻/中度污染天和重度污染天的粒径分布相似,均以粗模态形式存在,在4.7~5.8μm出现峰值;K^+、Cl^-在优良天、轻/中度污染天和重度污染天均为双峰分布,但峰值出现的粒径段有所改变.To characterize the size distribution of water soluble inorganic ions（ WSII） in haze days,particle samples were collected by an Andersen cascade impactor in Shijiazhuang from October 15 to November 14 in 2013,and the concentrations of eight kinds of WSII（ Na^＋,NH4^＋,K^＋,Mg^2＋,Ca^2＋,Cl^-,NO3^-and SO4^2-） during a typical haze episode were analyzed by ion chromatography. Sources and formation mechanism of WSII were analyzed based on their size distributions. The results showed that Shijiazhuang suffers serious air pollution during the autumn season. The daily average concentrations of PM10 and PM2. 5were（ 361. 2 ± 138. 7） μg·m^-3and（ 175. 6± 87. 2） μg·m^-3 and the daily average concentration of PM2.5 was 2. 3 times as high as the national secondary standard. The total water soluble inorganic ion concentrations（ TWSII） in clean days,light haze days and heavy haze days were（ 64. 4 ± 4. 6） μg·m^-3,（ 109. 9 ± 22. 0） μg·m^-3and（ 212. 9 ± 50. 1） μg·m^-3respectively. In addition,the ratio of secondary inorganic ions（ SNA： SO4^2-,NO3^-and NH4^＋） in TWSII increased from 44. 9% to 77. 6% as changed from clean days to the heavy haze days,suggesting the evolution of haze episodes mainly originated from the formation and accumulation of SNA. The size distributions of SO4^2-,NO3^-and NH4^＋were bimodal in clean days,peaking at 0. 43-0. 65 μm and 4. 7-5. 8 μm,respectively,which changed to unimodal distribution in both the light and heavy haze days,peaking at 0. 65-1. 1 μm. Owing to high humidity during the heavy haze days,the aqueous phase reactions of SO4^2-and NO3^-were likely promoted,which led to the transformation of condensation mode in clean days to the droplet mode in haze days. The size distributions of Na＋,Mg^2＋and Ca^2＋were different with that of SNA,which showed a coarse mode peaking at 4. 7-5. 8 μm both in clean and haze days,whereas K^＋and Cl^-showed a bimodal distribution both in clean and haze days,although the modal size was different i

关 键 词：霾污染 大气颗粒物 水溶性无机离子 粒径分布 石家庄 

分 类 号：X513[环境科学与工程—环境工程]