| 北京西北城区与清洁对照点夏季大气PM10的微观特征及粒度分布 |
| 摘要点击 1591 全文点击 1951 投稿时间：2002-11-05 修订日期：2003-02-19 |
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| 中文关键词 可吸入颗粒物 图像分析 扫描电镜(SEM) 单颗粒分析 粒度分布 |
| 英文关键词 PM10 image analysis Scanning Electron Microscopy (SEM) individual particle analysis size distribution |
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| 中文摘要 |
| 应用高分辨率场发射扫描电镜(FESEM)和图像分析技术研究了北京西北城区和清洁对照点非取暖期(2001年夏季)大气单个颗粒物的形貌特征以及PM10和PM2.5的数量-粒度和体积-粒度分布.研究表明,烟尘集合体在2个采样点都普遍存在,具有区域性污染的特征;不规则状矿物颗粒物多见于市区PM10样品中,而长条状石膏颗粒多出现在清洁对照点颗粒物样品中;在清洁对照点还观察到了生物质颗粒.PM10的数量-粒度分布呈双峰分布,主峰为0.2～0.5μm,次峰为在1～2.5μm但PM10的体积-粒度分布呈单峰分布,在1～2.5μm粒度范围内.综合分析得出,虽然粗颗粒,主要是矿物颗粒,在数量上对PM10贡献很小,但是对总体积,因此对总质量的贡献可能很大但在PM2.5中,烟尘集合体在数量和体积上均占优势. |
| 英文摘要 |
| Microscopic characteristics and size distribution of individual particles in the summer (2001) PM10 collected at a northwestern urban site and a clean air site in Beijing have been investigated using high resolution Field Emission Scanning Electron Microscopy (FESEM) and image analysis technologies. The soot aggregates were observed at both sampling sites, showing a characteristic regional pollution. The irregular mineral particles existed commonly at the urban site but were rarely seen at the clean air site. The elongated gypsums and biological particles were observed only at the clean air site. PM10 displayed a bimodal number-size distribution, with a higher peak in 0.2～0.5μm range and a lower peak in 1～2.5μm range. In contrast, volume-size distribution of PM10 exhibited a unimodal pattern with the peak in 1～2.5μm range. The coarse particles, mainly minerals, had a considerable contribution to the PM10 mass, although they were insignificant in number. In PM2.5, however, the soot aggregates were dominant both in number and mass. |
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