Collaborative Research: Transmission Electron Microscope (TEM) Studies of Soot, Organic Matter, and Associated Aerosol Particles During CalNex

一项三管齐下的研究计划将提供有关气溶胶颗粒在气候变化和健康中作用的新信息，以a）获得有关气溶胶颗粒（包括含金属纳米颗粒）的详细信息，这些信息是在加州期间在大洛杉矶地区收集的：空气质量和气候变化关系研究（CalNex 2010年）活动; B）开发和应用表征气溶胶颗粒中有机物的新方法;以及c）将这些结果纳入全球气候模型。在a）部分中，CalNex 2010期间对各种类型的气溶胶颗粒进行的透射电子显微镜（TEM）测量将提供有关形状、结构、光学特性、共生体和混合状态的数据，这些数据是其他方法无法获得的，并将补充其他小组收集的信息。a）部分的TEM结果将与使用其他气溶胶测量技术获得的结果进行比较。它们将与先前在墨西哥城及其周围进行的研究进行比较，从而有助于对特大城市气溶胶特性进行综合概述。部分B）将包括i）使用具有新的像差校正TEM的超高分辨率电子能量损失光谱法测定OM官能团和折射率，ii）使用TEM内的独特环境室测定OM吸湿性，以及iii）使用环境室中的受控步进加热测定OM挥发性。通过比较这些新兴的分析技术的结果，预计将获得新的微物理和化学信息的半挥发性和非挥发性部分的空气中的有机物在单个颗粒。在c）部分，a）和B）部分的结果将用于计算内部混合烟尘和OM的光学性质，然后将其纳入全球气候模式，以评估其广泛的影响，该研究将有助于理解人类面临的两个最重要的问题：人为全球气候变化和环境污染。准确预测气候变化需要详细了解气溶胶粒子的辐射强迫特性，这些分析将提供全面和独特的信息。确定含金属的空气纳米颗粒的出现和组成对于了解它们如何从工业来源运输以及它们如何与肺和其他组织相互作用从而影响健康非常重要。该项目还将有助于培训一名研究生和博士后研究员，包括广泛的指导活动和在专业会议上的演讲。此外，三维TEM图像将为年轻学生提供简单直观的图片，展示人类吸入的一些颗粒的外观。推广活动将包括与学校团体（包括小学）进行科学讲座，在年度地球日活动期间进行演讲，以及接受美国和海外新闻媒体的采访。

New information about the role of aerosol particles in climate change and health will be provided by a three-pronged research program to a) obtain detailed information about aerosol particles, including metal-bearing nanoparticles, collected in the greater Los Angeles area during the California: Research at the Nexus of Air Quality and Climate Change (CalNex 2010) campaign; b) develop and apply new ways of characterizing organic matter (OM) within aerosol particles; and c) integrate those results into a global climate model. In part a) transmission electron microscope (TEM) measurements of the various types of aerosol particles during CalNex 2010 will provide data regarding shapes, structures, optical properties, intergrowths, and mixing states that are unavailable by other methods and will complement the information collected by other groups. The TEM results of part a) will be compared to those obtained using other aerosol measurement techniques. They will be compared to those of a prior study in and around Mexico City, thereby contributing to a synthesized overview of aerosol properties in megacities. Part b) will include determinations of i) OM functional groups and refractive indices using ultrahigh-resolution electron energy-loss spectroscopy with new aberration-corrected TEMs, ii) OM hygroscopicity using a unique environmental cell within a TEM, and iii) OM volatility using controlled step heating in the environmental cell. By comparing results from these emerging analytical techniques, it is anticipated that new microphysical and chemical information will be obtained about the semi-volatile and non-volatile fractions of airborne OM within individual particles. In part c), the results of parts a) and b) will be used to calculate optical properties of internally mixed soot and OM, which will then be incorporated into global climate models to evaluate their broad impact.The research will contribute to understanding two of the most important problems confronting humanity: anthropogenic global climate change and environmental pollution. Accurate prediction of climate change requires detailed understanding of the radiative-forcing properties of aerosol particles, for which these analyses will provide comprehensive and unique information. Determining the occurrences and compositions of metal-bearing airborne nanoparticles is important for understanding how they are transported from their industrial sources and how they might interact with lung and other tissue and thus affect health. This project will also contribute to training of a graduate student and postdoctoral researcher, including extensive mentoring activities and presentations at professional meetings. In addition, three-dimensional TEM images will provide young students with simple and intuitive pictures of what some of the particles humans inhale look like. Outreach will include science talks to school groups (including grade schools), presentations during annual Earth Day events, and interviews with U.S. and overseas news media.