CAREER: Chemical Processing and Cloud Nucleation Activity of Soot Aerosol

这项提议的重点是烟尘颗粒与气相物质的相互作用，以及这可能如何改变它们作为冰和暖云核的能力。利用与化学离子质谱仪和云凝结核（CCN）计数器耦合的扩散室，研究气溶胶的化学老化和对流层上层条件下的冰核。对老化烟尘的温云凝结核效率也进行了测量。要解决的问题包括：1。烟尘气溶胶是否与氧化剂，如臭氧、OH自由基和NO2发生反应？氧化是对流层烟尘气溶胶的重要吸收途径吗？氧化的主要气相产物是什么？烟尘气溶胶的冰成核（IN）活性是什么？氧化反应或有机涂层会改变IN的活性吗？由于衰老过程，IN活性的改变和CCN活性的增加之间是否存在相关性？在教育部分，高中生将测量德克萨斯州休斯顿及其附近的降水。降水样本的表面张力测量将被制成并用作污染物水平的指示，作为地点的函数。在一门新的大气化学实验课程中，本科生将与高中生合作，对具有代表性的降水样品进行化学表征。结果将用于识别存在于城市环境中的可能作为冰核或CCN的化合物，并确定存在的有机化合物是否具有表面活性，从而能够改变云的成核活性。更广泛的影响还包括向高中学生讲授空气污染和正确的科学方法，这些学生将创建一个特定地点的数据集，其中包括休斯顿及其周边地区的降水数量和组成。研究生、本科生和高中生将共同参与这个项目并发表结果。这项研究的数据将被转换成对高中空气质量问题教学有用的格式。结果将广泛传播，包括在高中的开课和总结讲座。

This proposal focuses on the interactions of soot particles with gas phase species and how this may alter their ability to act as ice and warm cloud nuclei. Using a diffusion chamber coupled with a chemical ion mass spectrometer, and a cloud condensation nuclei (CCN) counter, chemical aging of aerosols will be studied and ice nucleation observed under upper tropospheric conditions. Measurements of warm cloud condensation nuclei efficiency of aged soot will also be conducted. Questions to be addressed include:1. Do soot aerosols react with oxidizing agents, such as ozone, OH radicals, and NO2? Is oxidation a significant sink for tropospheric soot aerosol? What are the major gas phase products of the oxidation?2. What is the ice nucleation (IN) activity of soot aerosol? Is IN activity altered by oxidation reactions or by organic coatings? Is there a correlation between altered IN activity and increased CCN activity due to aging processes?In the educational component, high school students will measure precipitation in and near Houston, TX. Surface tension measurements of the precipitation samples will be made and used as an indication of pollutant levels as a function of locale. Undergraduates in a new atmospheric chemistry laboratory course will coordinate with the high school students to chemically characterize representative precipitation samples. Results will be used to identify compounds present in the urban environment that could act as ice nuclei or CCN, and to determine whether organic compounds present are surface active and therefore capable of altering cloud nucleation activity. Broader impacts also include teaching about air pollution and proper scientific methods to high school students who will be creating a location-specific data set of the volume and composition of precipitation in and around Houston. Graduate, undergraduate and high school students will work jointly on this project and publish the results. Data from this study will be put into formats useful for teaching about air quality issues at the high school level. The results will be disseminated broadly, including kickoff and summary lectures at the high schools.