| 太原市大气颗粒物粒径和水溶性离子分布特征 |
| 摘要点击 2763 全文点击 1344 投稿时间：2015-11-27 修订日期：2016-01-22 |
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| 中文关键词 太原 大气颗粒物(PM10) 水溶性离子 粒径分布 来源解析 |
| 英文关键词 Taiyuan particle matter (PM10) water-soluble ions(WSIs) size distribution source analysis |
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| 中文摘要 |
| 在太原市于2014年7月至2015年4月利用TE-235分级采样器采集PM10分级颗粒物样品,通过离子色谱分析其中9种无机水溶性离子,报道了大气颗粒物(PM10)及其水溶性无机离子水平,探讨了其粒径分布、季节变化特征和来源.结果表明,采样期间太原市PM10日平均浓度水平为173.7 μg·m-3,超过了国家环境空气二级日标准限值(150 μg·m-3,GB3095-2012);冬季PM10浓度(199.1 μg·m-3)和春季(194.2 μg·m-3)较接近,远高于夏季水平(127.7 μg·m-3).PM10在<0.95 μm和3.0~7.2 μm粒径段处呈双峰分布.PM10中总离子浓度季节变化为冬季> 夏季> 春季,其中SO42-、NO3-和NH4+是主要离子,占总离子的质量分数为66%~80%.分级离子中,SO42-、K+、NH4+、Cl-以及冬、春季的NO3-在<0.95 μm段呈单峰分布;Ca2+、Mg2+和夏季NO3-均在<0.95 μm和3.0~7.2 μm段呈双峰分布.相关性分析显示,风速增大对冬夏季的颗粒物及其水溶性离子有稀释作用,但春季沙尘天气则会导致其升高.通过NO3-/SO42-和Mg2+/Ca2+比值发现,太原市颗粒物中NO3-和SO42-主要来自于燃煤排放,Mg2+和Ca2+来源为扬尘和煤燃烧排放. |
| 英文摘要 |
| The distributions of size-segregated particles (PM10) and water-soluble ions (WSIs) in Taiyuan were studied from July 2014 to April 2015 by TE-235 aerosol sampling and ion chromatography analyzing. As the results shown, the daily PM10 level was 173.7 μg·m-3, which exceeded the Grade Ⅱ limitation value in the Ambient Air Quality Standard (150 μg·m-3, GB 3095-2012). PM10 levels varied seasonally, and its were 199.1 and 194.2 μg·m-3 in winter and spring, respectively, which were much higher than those in summer. The PM10 size-segregated was bimodal distribution for the range of 0-0.95 and 3.0-7.2 μm. The concentration of WSIs was the highest in winter, followed by summer and spring. SO42-, NO3- and NH4+ were the main water soluble ions and accounted for 66% to 80% of the total WSIs. SO42-, K+, NH4+ and Cl- showed a unimodal distribution at <0.95 μm in all samples, while Ca2+ and Mg2+ showed a bimodal distribution at <0.95 μm and 3.0-7.2 μm. NO3- showed a unimodal size distribution at <0.95 μm in winter and spring, compared with a bimodal distribution at <0.95 μm and 3.0-7.2 μm in summer. By the correlation analysis, PM10 and WSIs decreased with the increase of wind speed in summer and winter other than in spring for the road-dust re-suspension by strong wind. Based on the ratio analysis of NO3-/SO42- and Mg2+/Ca2+, coal combustion was the main source of NO3- and SO42-, while Mg2+ and Ca2+ were mainly from the dust and coal combustion. |
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