Soot Source Identification by Laser Derivatization (SSILD)

1236757范德沃尔煤烟的物理结构和化学成分各不相同，这取决于其来源，主要是柴油发动机，燃烧器或发电厂。先前的研究通过对HRTEM图像提取的物理结构参数进行量化，表明煤烟的近原子水平结构依赖于来源。原则上，这允许识别烟灰来源及其对任何特定受体位点的贡献。然而，许多结构方面是微妙的，颗粒的可变化学仍然没有解决。本项目将研究瞬态激光处理的过程，以突出成分和结构的差异，从而独特而独特地识别烟灰的来源。脉冲激光加工的意义在于，根据初始化学和结构的结合，材料会转变成独特的图案。目标是开发基于激光的加工作为一种分析工具，并确定最佳转换的工艺条件和操作参数。实现这一目标的具体目标包括确定激光操作参数，确定对初始结构和成分的依赖，证明不同来源的烟灰之间的区别，并对结构变化进行统计量化。重型卡车、发电厂甚至喷气式飞机起飞时都会排放烟尘。煤烟是不完全燃烧的副产品。它的形成反映了燃烧效率低下，其释放会带来健康风险和环境问题。根据美国环境保护署的说法，人为排放的烟尘会导致许多负面的健康后果，包括哮喘、心律失常甚至住院。新的发现表明，煤烟可能会导致北极附近发生的气候变化，比如加速海冰和雪的融化以及改变大气温度。虽然黑碳是疏水的（憎水），但在其表面发生的化学和物理变化可以使它变得亲水（亲水）。这些变化决定了烟尘对云形成的贡献，它对大气冲刷的敏感性以及它对大气非均相反应的参与。所有这些过程都显著影响大气辐射平衡。最近的估计表明，黑碳辐射强迫几乎占二氧化碳辐射强迫的一半。因此，跟踪煤烟的分散和源头识别是解决这些问题的起点。

1236757Vander WalSoot varies, in physical structure and chemical composition, as dependent upon its source, primarily diesel engines, combustors or power plants. Prior studies have shown the near atomic level structure of soot to be dependent upon the source via quantification of physical structure parameters extracted from HRTEM images. In principle this permits identification of the soot source and its contribution to any particular receptor site. Yet many structural aspects are subtle and the variable chemistry of the particles remains unaddressed. This project will investigate the process of transient laser processing to highlight compositional and structural differences, thereby distinctively and uniquely identifying the source of the soot. The significance of pulsed laser processing is that the material transforms to yield distinctive patterns, dependent upon the combination of initial chemistry and structure. The goal is then to develop the laser-based processing as an analytical tool and identify the process conditions and operational parameters for optimal transformation. Specific objectives directed towards achieving this goal include identifying laser operational parameters, defining dependence upon initial structure and composition, demonstrating differentiation between soot from different sources and quantifying the structural changes statistically.Soot is routinely emitted from heavy-duty trucks, power plants and even jet aircraft such as upon takeoff. Soot is the byproduct of incomplete combustion. Its formation reflects combustion inefficiency and its release imposes health risks and environmental concerns. According to the EPA, soot from anthropogenic sources is responsible for many negative health consequences including asthma, heart arrhythmias and even hospitalizations. New findings show soot may be contributing to climate changes happening near the North Pole, such as accelerating melting of sea ice and snow and changing atmospheric temperatures. Although black carbon is hydrophobic (water hating), chemical and physical changes occurring at its surface can cause it to become hydrophilic (waer loving). Such changes determine soot's contribution to cloud formation, its susceptibility to atmospheric washout and its participation in atmospheric heterogeneous reactions. All such processes significantly impact the atmospheric radiative balance. Recent estimates place black carbon radiative forcing as nearly half that attributed CO2. Therein tracking soot dispersion and source identification is a starting point to address these issues.