Chirality in Aerosol Chemistry

化学部的环境化学科学（ECS）计划，大气和地球空间科学部的大气化学计划以及国际科学与工程办公室（OISE）将支持西北大学的Franz盖革教授和哈佛大学的Scot Martin教授的合作研究计划。盖革教授、马丁教授和他们的学生将联合收割机结合实验室和现场实验来验证这一假设：就像一个人的两只手可以用绳子产生手性字符串图形一样，手性生物源挥发性有机化合物的氧化可以在大气颗粒物中产生手性有机物质，对进一步的化学反应性和物理性质产生重要影响。这两个研究小组将使用一个环境室，在控制良好的对流层相关条件下，从手性生物挥发性有机化合物的混合物中合成和分析手性次生有机材料。新形成的次生有机物质的气候相关特性将作为气相中立体异构混合物的函数进行研究，并使用非线性光学化学成像和非线性光学激光光谱学与有机物质的化学组成和手性相关。实验室模型研究将以亚马逊盆地中部收集的有机气溶胶颗粒的化学成分、粒度分布和来源为基准，该盆地的特点是原始条件，人为输入最少。研究手性气溶胶化学有可能发现全新的气溶胶过程，这可能有助于改善对气候系统辐射强迫的预测。手性大气立体化学也可以发展成为一种手性标记物，以区分燃烧的化石燃料和燃烧的森林。这可能会改变目前的生物源排放与人为排放的源解析方法，这些方法通常基于昂贵的同位素分析。该项目将为希望在具有重大社会意义的领域从事专业科学事业的学生，包括代表性不足的群体的成员提供极好的培训机会。

The Environmental Chemical Sciences (ECS) program of the Division of Chemistry, the Atmospheric Chemistry program of the Division of Atmospheric and Geospace Sciences and the Office of International Science and Engineering (OISE) will support the collaborative research program of Prof. Franz Geiger of Northwestern University and Prof. Scot Martin of Harvard University. Professor Geiger, Professor Martin, and their students will combine laboratory and field experiments to test the hypothesis that just like the two hands of one person can use string to produce chiral string figures, the oxidation of chiral biogenic volatile organic compounds can produce chiral organic material in atmospheric particles, with important effects on further chemical reactivity and physical properties. The two research groups will use an environmental chamber to synthesize and analyze chiral secondary organic material from mixes of chiral biogenic volatile organic compounds under well-controlled tropospherically relevant conditions. Climate-related properties of the newly formed secondary organic material will be investigated as a function of the stereoisomeric mix in the gas phase and correlated with the chemical composition and chirality of the organic material using nonlinear optical chemical imaging and nonlinear optical laser spectroscopy. Laboratory model studies will be benchmarked against chemical composition, size distribution, and origin of organic aerosol particles collected in the central Amazon Basin, which features pristine conditions with minimal anthropogenic input. Studying chiral aerosol chemistry has the potential to allow for the discovery of fundamentally new aerosol processes, which could help improve the prediction of radiative forcing of the climate system. Chiral atmospheric stereochemistry could also be developed towards a chiral marker to distinguish, for instance, burning fossil fuels from burning forests. This could potentially transform current methods for source apportionment of biogenic vs. anthropogenic emissions, which are commonly based on costly isotope analysis. The project will provide excellent training opportunities to students, including to members of under-represented groups, who wish to pursue a professional scientific career in an area of great societal importance.