| 兰州市夏秋季颗粒物谱分布特征研究 |
| 摘要点击 2790 全文点击 1332 修订日期：2011-06-27 |
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| 中文关键词 兰州 大气颗粒物 谱分布 聚类分析 气象条件 |
| 英文关键词 Lanzhou atmospheric particle size distribution cluster analysis meteorological condition |
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| 中文摘要 |
| 采用 APS-3321空气动力学粒径谱仪对兰州市 2010年 8~10月 0.5~20 μm大气颗粒物浓度及其谱分布进行了实时监测,并通过聚类分析方法结合气象观测数据对体积浓度谱特征及其影响因素进行了分析.以阐明兰州市夏秋季不同粒径段颗粒物浓度水平和粒谱分布特征及其成因.结果表明,0.5~20 μm大气颗粒物小时平均数浓度、表面积浓度和体积浓度分别为(108.1±92.2)个·cm-3、(282.9±267.9)μm2·cm-3和(92.2±127.3) μm3·cm-3,细粒子(0.5~2.5 μm)分别占0.5~20 μm大气颗粒物数浓度、表面积浓度和体积浓度的98.7%、73.8%和52.9%.观测期间数浓度谱呈单峰分布,峰值出现在积聚模态,表面积浓度谱和体积浓度谱呈双峰型,峰值分别位于积聚模态和粗模态.颗粒物体积浓度谱主要有7类代表不同源和气象条件影响的分布型.受浮尘天气和局地扬尘影响的颗粒物体积谱分布在粗模态有明显的峰,而受机动车直接燃烧排放和二次扬尘影响的颗粒物体积谱分布呈双峰型,峰值分别位于积聚模态和粗模态. |
| 英文摘要 |
| Atmospheric particle size distributions (size range 0.5-20 μm) were measured using aerodynamic particle sizer (APS-3321) from August 1st to October 31st in Lanzhou. Variations of particle concentrations and properties of volume concentration distributions were analyzed through cluster analysis. The main objective of this study was to identify factors affecting the particle size distributions in Lanzhou. The hourly averaged particle number, surface area and volume concentrations are (108.1±92.2) cm-3, (282.9±267.9) μm2·cm-3 and (92.2±127.3) μm3·cm-3, respectively. The number, surface area and volume concentrations of fine particles (0.5-2.5 μm) account for 98.7%, 73.8% and 52.9% of the total particle concentrations in 0.5-20 μm, respectively. The size distribution of number concentrations is unimodal with a peak at accumulation mode. The size distributions of surface area and volume concentrations are bimodal with peaks at accumulation mode and coarse mode, respectively. The size distributions of particle volume concentrations mainly have 7 clusters, indicating the effect of different sources and meteorological conditions. Coarse mode particles are dominant in particle volume size distributions affected by wind-borne dust and on dust days, while that affected by motor vehicle combustion emissions and traffic resuspended dust are characterized by bimodal with peaks at accumulation mode and coarse mode, respectively. |
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