| 太原大气颗粒物中水溶性无机离子质量浓度及粒径分布特征 |
| 摘要点击 4245 全文点击 1723 投稿时间：2016-03-02 修订日期：2016-04-22 |
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| 中文关键词 水溶性无机离子 季节变化 粒径分布 来源 太原 |
| 英文关键词 water-soluble inorganic ions seasonal variation size distribution source Taiyuan |
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| 中文摘要 |
| 为研究太原大气颗粒物中水溶性无机离子的质量浓度水平、季节变化和粒径分布特征，于2012年6月～2014年5月使用惯性撞击式分级采样器采集大气颗粒物样品，并用离子色谱分析了其中的水溶性无机离子组成.结果表明，PM1.1、PM2.1和PM9中总水溶性无机离子浓度平均值分别为（15.39±9.91）、（21.10±15.49）和（36.34±18.51）μg·m-3.PM1.1和PM2.1中，二次离子（SO42-、NO3-和NH4+）占总水溶性无机离子质量分数最高；PM9中SO42-和Ca2+占比较高.各粒径段中SO42-和NH4+季节变化特征相似，均为冬夏季节高、春秋季节低；NO3-、K+和Cl-季节变化特征一致：冬季 >秋季 >春季 >夏季；Ca2+和Mg2+季节变化特征一致：春季 >冬季 >秋季 >夏季.SO42-和NH4+为细模态单峰分布，春秋季节在0.43～0.65 μm处出现峰值，而夏季出现在0.65～1.1 μm处，细粒径段峰值出现由凝结模态向液滴模态转移的现象.NO3-为双模态离子，冬季在0.43～2.1 μm出现明显细粒径段峰值，夏季在4.7～5.8 μm出现明显粗模态峰值.K+、Na+和Cl-为双模态离子，分别在0.43～1.1和4.7～5.8 μm出现峰值；Ca2+、Mg2+和F-呈粗模态单峰分布，在4.7～5.8 μm出现峰值.主成分分析结果显示，水溶性无机离子来源主要是二次源、燃煤、工业源、生物质燃烧和土壤尘或降尘. |
| 英文摘要 |
| Size-resolved filter samples were collected in Taiyuan every other week from June 2012 to May 2014. The mass concentrations of water-soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3- and SO42-) were measured by ion chromatography. The results showed that the total concentrations of measured water-soluble ions were (15.39±9.91), (21.10±15.49) and (36.34±18.51) μg·m-3 in PM1.1, PM2.1 and PM9, respectively. In PM1.1 and PM2.1, secondary water-soluble ions (SO42-, NO3- and NH4+) comprised 87.59% and 86.30% of all water-soluble ions, respectively, while in PM9, SO42- and Ca2+ comprised 32.78% and 28.54% of all water-soluble ions, respectively. SO42- and NH4+ had higher concentrations in winter and summer, and lower in spring and autumn. NO3-, K+and Cl- presented similar seasonal variation with a descending order of winter >autumn >spring >summer, and Ca2+ and Mg2+ followed the sequence of spring >winter >autumn >summer. SO42- and NH4+ showed a unimodal size distribution and the peak in the fine mode shifted from 0.43-0.65 μm in spring and autumn to 0.65-1.1 μm in summer. NO3- showed a bimodal size distribution. NO3- and NH4+ were dominated by the fine mode peaking at 0.43-2.1 μm in winter, and NO3- was dominated by the coarse mode peaking at 4.7-5.8 μm in summer. K+, Na+and Cl- also showed a bimodal size distribution with the fine mode at 0.43-1.1 μm and the coarse mode at 4.7-5.8 μm. Ca2+, Mg2+ and F- were unimodal with the peak in the coarse mode of 4.7-5.8 μm. On heavily polluted days, the mass concentrations of secondary water-soluble ions and Cl- accumulated, and secondary water-soluble ions were unimodal with the peak in the fine mode of 1.1-2.1 μm. However, on clear days, secondary water-soluble ions showed a bimodal size distribution with the fine mode at 0.43-0.65 μm and the coarse mode at 4.7-5.8 μm. The peak of secondary water-soluble ions in the fine mode shifted. PCA analysis showed that the sources of water-soluble ions were dominated by the secondary formation, coal combustion, industrial emission, biomass burning, and soil particles or falling dust. |
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