Extensive Soot Compaction by Cloud Processing from Laboratory and Field Observations
Extensive Soot Compaction by Cloud Processing from Laboratory and Field Observations
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DOI：
10.1038/s41598-019-48143-y
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发表时间：
2019-08-14
影响因子：
4.6
通讯作者：
Mazzoleni, Claudio
中科院分区：
文献类型：
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作者：
Bhandari, Janarjan;China, Swarup;Mazzoleni, Claudio
碳质材料燃烧过程中会形成烟尘颗粒，影响气候和空气质量。当它们新鲜发射时，它们通常是类分形的聚集体。在大气老化后，它们可以作为云凝结核，水凝结或蒸发将它们重组为更紧密的聚集体，影响它们的光学、空气动力学和表面性质。在这里，我们调查了来自不同地点、不同环境和老化条件的环境烟尘颗粒的形态。我们使用了电子显微镜，并显示云处理后广泛的烟尘压实。我们进一步进行了实验室实验，以模拟受控条件下的大气云过程。我们发现，在蒸发云滴后采样的烟尘颗粒比新排放的和间隙烟尘要紧密得多，这证实了云处理，而不仅仅是暴露在高湿度下，压缩了烟尘。我们的发现对如何在数值模型中表示烟尘颗粒的辐射、表面和空气动力学特性以及命运具有重要意义。
Soot particles form during combustion of carbonaceous materials and impact climate and air quality. When freshly emitted, they are typically fractal-like aggregates. After atmospheric aging, they can act as cloud condensation nuclei, and water condensation or evaporation restructure them to more compact aggregates, affecting their optical, aerodynamic, and surface properties. Here we survey the morphology of ambient soot particles from various locations and different environmental and aging conditions. We used electron microscopy and show extensive soot compaction after cloud processing. We further performed laboratory experiments to simulate atmospheric cloud processing under controlled conditions. We find that soot particles sampled after evaporating the cloud droplets, are significantly more compact than freshly emitted and interstitial soot, confirming that cloud processing, not just exposure to high humidity, compacts soot. Our findings have implications for how the radiative, surface, and aerodynamic properties, and the fate of soot particles are represented in numerical models.