Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC, V6T 1Z4, Canada.
Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC, V6T 1Z4, Canada.
Chemosphere. 2020 Aug;252:126532. doi: 10.1016/j.chemosphere.2020.126532. Epub 2020 Mar 23.
Incomplete combustion is the main source of airborne soot, which has negative impacts on public health and the environment. Understanding the morphological and chemical evolution of soot is important for assessing and mitigating the impact of soot emissions. Morphological and chemical structures of soot are commonly studied using microscopy or spectroscopy, and the best technique depends on the parameter of interest and the stage of soot formation considered (i.e., maturity). For the earliest stages of soot formation, particles exhibit simple morphology yet complex and reactive chemical composition, which is best studied by spectroscopic techniques sensitive to the large number of soot precursor species. The only microscope that can offer some morphological information at this stage is the scanning probe microscopy, which can image single polycyclic aromatic hydrocarbons, the precursors of soot. A broader range of types of spectrometers and microscopes can be used by increasing the soot maturity. Mature soot is primarily carbon, and exhibits complex fractal-like morphology best studied with electron microscopy and techniques sensitive to thin oxide or organic coatings. Each characterization technique can target different morphological and chemical properties of soot, from the early to the late stage of its formation. Thus, a guideline for the selection of the appropriate technique can facilitates studies on environmental samples involving the presence of soot.
不完全燃烧是空气中烟尘的主要来源，对公众健康和环境有负面影响。了解烟尘的形态和化学演变对于评估和减轻烟尘排放的影响很重要。通常使用显微镜或光谱学来研究烟尘的形态和化学结构，最佳技术取决于感兴趣的参数以及烟尘形成的阶段（即成熟度）。对于烟尘形成的最早阶段，颗粒表现出简单的形态，但化学组成复杂且具有反应性，这最好通过对大量烟尘前体物质敏感的光谱技术来研究。在这个阶段，唯一能够提供一些形态信息的显微镜是扫描探针显微镜，它可以对作为烟尘前体的单环芳香烃进行成像。通过增加烟尘的成熟度，可以使用更广泛类型的光谱仪和显微镜。成熟的烟尘主要是碳，其具有复杂的分形形态，最好使用电子显微镜和对薄氧化物或有机涂层敏感的技术进行研究。每种特性化技术都可以针对烟尘形成的早期到晚期的不同形态和化学特性进行研究。因此，选择合适技术的指南可以促进涉及烟尘存在的环境样品的研究。
