Measured Organic Particle Types with Molecular Modeling of their Volatility and Uptake Properties

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。本研究提出了一种结合测量、分析和建模的方法，以解决三个相关任务中的这些不确定性。首席研究员（PI）将：(1)使用扫描透射x射线显微镜（STXM）和傅里叶变换红外光谱（FTIR）收集和分析烟雾室中产生的有机气溶胶的官能团组成和形态（包括单个颗粒内的化学分布），作为“年龄”（氧化剂暴露）的函数；(2)分析我们在11次野外活动中收集的大约1000个环境颗粒光谱档案的形态，并将其与雾霾室颗粒和其他已公布的颗粒类型进行比较；(3)通过模型模拟确定观测到的有机化合物类型与形态之间的联系。对于每种类型，PI还将计算这些颗粒在大气条件下表现出的挥发性和吸水性。考虑到我们感兴趣的大气颗粒大小的广泛范围以及模拟单个分子的计算局限性，这项工作将包括用于小于20纳米颗粒的“全颗粒”技术和用于估计适合描述大气模型中较大颗粒的参数的“平板”技术。本项目为两名博士后和一名研究生提供了一套通过实验和计算方法参与科学事业的培训机会。这项工作在三个美国学术机构之间建立了新的合作关系。此外，PI还将让学生们总结我们最近对气溶胶行为的发现，并将其发布在由研究人员维护的“拓展”网页上。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This research presents a combined measurement, analysis, and modeling approach that addresses these uncertainties in three related tasks. The Principal Investigator (PI) will: (1) collect and analyze organic aerosols generated in smog chambers for functional group composition and morphology (including chemical distribution within individual particles) using Scanning Transmission X-ray Microscopy (STXM) and Fourier Transform Infrared Spectroscopy (FTIR), as a function of "age" (oxidant exposure); (2) analyze the morphology of our archive of approximately 1000 ambient particle spectra collected during eleven field campaigns in comparison to the smog chamber particles and other published particle types; and (3) identify the links between the observed organic compound types and morphologies via model simulations. For each type, the PI will also calculate the volatility and water uptake properties that these particles exhibit in atmospheric conditions. Given the wide range of atmospheric particle sizes of interest and the computational limitations of simulating individual molecules, the work will include "full particle" techniques for particles smaller than 20 nanometers and "slab" techniques for estimating parameters suitable for describing larger particles in atmospheric models.This project creates a set of training opportunities for two postdoctoral scholars and one graduate student who will participate in the scientific enterprise through engagement in experimental and computational methods. The work establishes a new collaboration among three U.S. academic institutions. In addition, the PI will involve students in summarizing our recent findings on aerosol behavior for a broader audience for posting on the "Outreach" web page maintained by the investigators.