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

关于气溶胶颗粒在气候变化和健康中的作用的新信息将通过一个三管齐下的研究计划提供：a)获取关于气溶胶颗粒的详细信息，包括在加州：空气质量与气候变化联系研究(CalneX 2010)活动期间在大洛杉矶地区收集的含金属纳米颗粒；b)开发和应用表征气溶胶颗粒中有机物(OM)的新方法；以及c)将这些结果整合到全球气候模型中。A)在2010年CalneX期间对各种类型的气溶胶颗粒进行的透射电子显微镜测量将提供其他方法无法获得的关于形状、结构、光学性质、相互生长和混合状态的数据，并将补充其他小组收集的信息。A)部分的瞬变电磁测量结果将与使用其他气溶胶测量技术获得的结果进行比较。它们将与墨西哥城及其周围先前的研究结果进行比较，从而有助于对特大城市的气溶胶特性进行综合概述。B)部分将包括：i)使用超高分辨率电子能量损失光谱和新的经像差校正的TEMS来测定OM官能团和折射率；ii)使用透射电子显微镜中独特的环境单元来测定OM的吸湿性；以及iii)使用环境单元中的受控阶梯加热来测定OM的挥发性。通过比较这些新出现的分析技术的结果，预计将获得关于单个颗粒中空气中有机物的半挥发性和非挥发性部分的新的微物理和化学信息。在c)部分，a)和b)部分的结果将用于计算内部混合的碳烟和OM的光学性质，然后将其纳入全球气候模式，以评估它们的广泛影响。这项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。对气候变化的准确预测需要详细了解气溶胶颗粒的辐射强迫特性，这些分析将为此提供全面和独特的信息。确定空气中金属纳米粒子的赋存状态和组成，对于了解它们如何从其工业来源运输，以及它们可能如何与肺和其他组织相互作用从而影响健康非常重要。该项目还将帮助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陈述。此外，三维电子显微镜图像将为年轻学生提供简单直观的图像，了解人类吸入的一些颗粒物的样子。外展将包括向学校团体(包括小学)进行科学讲座，在一年一度的地球日活动中发表演讲，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.