| 摘要: |
| 为了研究冬季不同粒径大气颗粒物中水溶性无机离子(WSIIs)污染特征和来源，于2017年1月5日～2月4日在呼和浩特市采集了PM1、PM2.5和PM10样品，使用离子色谱法测定了8种WSIIs，分析了其组成、存在形式和二次转化特征。结果表明：灰霾天PM1、PM2.5和PM10中WSIIs日均浓度是清洁天的3.1、3.1和3.0倍，分别占三种颗粒物质量浓度的43.0%、45.9%和34.4%。灰霾天硫酸盐、硝酸盐和铵盐(SNA)是WSIIs的主要离子，分别占三种颗粒物中WSIIs的81.9%、83.1%和81.0%。除夕PM1、PM2.5和PM10中Cl-浓度分别是清洁天的7.5、6.9和6.3倍，Mg2+浓度分别是清洁天的11.2、8.3和5.6倍，说明烟花燃放对呼和浩特市大气颗粒物中Cl-和Mg2+有较大贡献。离子平衡结果表明，PM1和PM2.5中阴离子和阳离子当量浓度比值（AE/CE）大于1，而PM10中AE/CE比值小于1，存在明显的酸碱差异。除夕三种颗粒物AE/CE比值分别为2.3、1.8和1.6，颗粒物呈明显酸性，这主要与燃放烟花排放大量的阴离子有关。灰霾天，离子多以NH4NO3、(NH4)2SO4和Ca(NO3)2的形式存在。除夕离子不仅以NH4NO3、(NH4)2SO4和Ca(NO3)2的形式存在，NO3-和Cl-可能还以KNO3、KCl和MgCl2的形式存在。二次转化特征结果表明，硫酸盐和硝酸盐不仅来源于一次排放，还来源于气态前体物的非均相液相反应二次生成。 |
| 关键词: 呼和浩特 颗粒物 水溶性无机离子 存在形式 离子平衡 |
| DOI： |
| 分类号:X |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目）；内蒙古自治区科技计划项目 |
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| Pollution Characteristics of Water-soluble Inorganic Ions in PM1、 PM2.5 and PM10 in Winter in Hohhot |
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SUN Bing,SUN Ying,REN Hui-fang,ZHOU Hai-jun
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| Abstract: |
| To investigate the characteristics and sources of water-soluble inorganic ions (WSIIs) in particulate matter with different particle sizes during winter, PM1, PM2.5 and PM10 samples were collected in Hohhot from January 5 to February 4, 2017. Eight kinds of WSIIs were determined using ion chromatography. The compositions, existing forms and secondary transformation characteristics were analyzed. The results suggested that the average daily WSIIs concentration of PM1, PM2.5 and PM10 in haze days were 3.1, 3.1 and 3.0 times of that observed in clean days, accounting for 43.0%, 45.9% and 34.4% of the total mass concentration of particulate matter, respectively. Sulfate, nitrate and ammonium (SNA) are the predominant ions of WSIIs in haze days, accounting for 81.9%, 83.1% and 81.0% of the total WSIIs in the three kinds of particulate matter, respectively. The concentration of Cl- in PM1, PM2.5 and PM10 on New Year's Eve was 7.5, 6.9 and 6.3 times of that observed in clean days, respectively. The concentration of Mg2+ on New Year's Eve was 11.2, 8.3 and 5.6 times of that observed in clean days, respectively. It indicated that fireworks have a greater contribution to the Cl- and Mg2+ in particulate matter in Hohhot. The ratio of anion to cation equivalent concentration (AE/CE) in PM1 and PM2.5 were higher than 1, whereas that in PM10 was lower than 1, highlighting noticeable differences in aerosol acidity. The AE/CE of the three kinds of particulate matter on New Year's Eve were 2.3, 1.8 and 1.6, respectively. The result indicated that the three kinds of particulate matter were obviously acidic, which was mainly related to the large number of anions emitted by fireworks. During haze days, ions predominantly existed as NH?NO?, (NH?)?SO?, and Ca(NO?)?, while on New Year's Eve, additional ionic forms such as KNO?, KCl, and MgCl? were also present. The results of secondary transformation show that sulfate and nitrate are not only derived from primary emission, but also from the secondary formation of heterogeneous reaction from gaseous precursors. |
| Key words: Hohhot Particulate Matter Water soluble inorganic ions existence form ion balance |
