Aged status of soot particles during the passage of a weak cyclone in Beijing
Aged status of soot particles during the passage of a weak cyclone in Beijing
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北京弱气旋过程中烟尘颗粒的老化状况
DOI：
10.1016/j.atmosenv.2011.02.056
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发表时间：
2011-05
影响因子：
5
通讯作者：
Zhang, Daizhou
中科院分区：
文献类型：
--
作者：
Niu, Hongya;Shao, Longyi;Zhang, Daizhou
2009年4月18 ~ 21日，在北京城区一次弱天气气旋过境，空气质量相对较好的情况下，利用电子显微镜对北京城区大气颗粒物进行了研究。从旋风分离器的不同阶段收集的颗粒的特征在于它们的形状，尺寸和元素组成。烟尘颗粒占主导地位，并集中在0.2-1.0 μm的尺寸范围内，很少检测到超出此范围的颗粒。大多数烟灰颗粒表现出老化的形状，即具有液体涂层的收缩簇（所谓的核-壳结构），与新鲜烟灰颗粒的开放小球的链或团聚体形状相比。比较了前额叶和后额叶空气中颗粒物的形态。额前空气颗粒物平均当量直径为0.36-0.38 μm，额后空气颗粒物平均当量直径为0.35-0.41 μm。超过50%的颗粒的纵横比在1.0和1.4之间，其余的通常小于2.0。就圆形因子而言，57-64%的前额叶空气颗粒物和41-51%的后额叶空气颗粒物出现在0.6-1.0之间。这些结果表明，尽管锋面后空气质量远好于锋面前，但锋面前和锋面后空气中碳烟粒子的老化状态没有很大差异，表明即使在污染程度较轻的空气中，链状或聚集状的新鲜碳烟粒子也能迅速转变为核壳结构。此外，初步估算表明，老化导致颗粒中烟灰部分的横截面积减小。
Atmospheric particles at an urban site in Beijing from Apr. 18 to 21, 2009, when a weak synoptic cyclone passed and the air quality was relatively fine, were investigated by using electron microscopes. Particles collected from different stages of the cyclone were characterized by their shape, size and elemental composition. Soot particles were predominant and concentrated in the size range of 0.2–1.0 μm, and out of this range were rarely detected. Most of the soot particles exhibited aged shape, i.e. shrunk clusters with liquid coating (the so-called core-shell structure), compared to the open spherule’s chain or agglomerate shape of fresh soot particles. Morphologies of the particles in the prefrontal and postfrontal air were compared. The mean equivalent diameter of the particles in the prefrontal air was 0.36–0.38 μm and in the postfrontal air was 0.35–0.41 μm. More than 50% of the particles had aspect ratios between 1.0 and 1.4, and the remains frequently smaller than 2.0. In terms of circularity factor, 57–64% particles in the prefrontal air and 41–51% in the postfrontal air appeared in the range of 0.6–1.0. These results indicate that the aged status of soot particles in the prefrontal and postfrontal air were not very different, although the quality of the postfrontal air was much better than that of the prefrontal air, suggesting that fresh soot particles in chain or aggregate shape could be modified into core-shell structure rapidly even in less polluted air. In addition, a primary estimate showed that aging had caused the decrease of the cross-section areas of soot parts in the particles.
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影响因子：
--
作者：
Zhijun Wu;Min Hu;Shang Liu;B. Wehner;S. Bauer;Andreas Ma ßling;A. Wiedensohler;T. Petäjä;
通讯作者：
Zhijun Wu;Min Hu;Shang Liu;B. Wehner;S. Bauer;Andreas Ma ßling;A. Wiedensohler;T. Petäjä;
DOI：
--
发表时间：
2010-05
期刊：
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影响因子：
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影响因子：
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作者：
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通讯作者：
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影响因子：
4.4
作者：
Adachi, Kouji;Chung, Serena H.;Buseck, Peter R.
通讯作者：
Buseck, Peter R.