Physical and Chemical Properties of Atmospheric Organic Aerosol

小行星9508051 有机气溶胶是大气颗粒物的重要组成部分，无论是在城市、农村还是偏远地区。有机化合物平均占洛杉矶等城市污染地区细气溶胶质量的35%，其在全球范围内的来源估计与硫酸盐相似。它们是气溶胶对气候的直接和间接辐射强迫的组成部分。大气气溶胶造成重大的环境风险（健康问题、能见度下降），部分原因是这些有机化合物。对烃类光氧化的低挥发性产物冷凝而原位形成二次有机气溶胶的情况仍然知之甚少。 该项目将研究有机化合物从气体到气溶胶相的传质。将通过测量其混合物的蒸汽压来研究主要有机气溶胶组分在气相和气溶胶相之间的平衡分配。这些有机化合物的缩合速率将是 定量的各种模式无机和有机气溶胶基质和计算的调节系数。将确定有机化合物对NH4NO3蒸发速率的影响，以及有机膜对有机和无机气溶胶生长速率的影响。建议的实验系统是基于串联差分迁移率分析仪技术。研究结果将被纳入一个最先进的气溶胶模型，模型输出将用现有的最佳城市空气质量数据集进行测试。 该项目的教育工作将侧重于为工程师开设环境课程。 将编写一本大气化学教科书，用于其中一门课程。探讨了计算机技术在化学工程教育中的应用。本科生将直接通过一年的高级研究项目和间接通过工程和公共政策项目课程参与研究。最后，通过卡内基梅隆大学的跨课程环境方案开发环境模块将有助于所有工程师的环境教育。

9508051 Pandis Organic aerosol is an important component of ambient particulate matter, whether in urban, rural, or remote areas. Organic compounds represent on average 35% of the fine aerosol mass in urban polluted areas like Los Angeles and their sources on a global scale are estimated to be similar to those of sulfate. They are an integral part of the direct and indirect radiative forcing of climate by aerosols. Atmospheric aerosol pose significant environmental risks (health problems, visibility degradation) in part because of these organic compounds. The in-situ formation of secondary organic aerosol by condensation of low volatility products of the photooxidation of hydrocarbons remains poorly understood. This project will investigate the mass transfer of organic compounds from the gas to the aerosol phase. The equilibrium partitioning of the major organic aerosol components between the gas and aerosol phases will be studied by measuring the vapor pressures of their mixtures. The condensation rates of these organic compounds will be quantified on a variety of model inorganic and organic aerosol substrates and the accommodation coefficients calculated. The effects of the organic compounds on the evaporation rate of NH4NO3 will be determined, as well as the influence of organic films on the rate of growth of organic and inorganic aerosols. The proposed experimental system is based on the Tandem Differential Mobility Analyzer technique. The results will be incorporated into a state-of-the-art aerosol model and the model output will be tested with the best available urban air quality data set. The educational efforts of this project will focus on the development of environmental classes for engineers. A textbook in atmospheric chemistry will be developed and used for one of these classes. The application of computer technology to the education of chemical engineers will be explored. Undergraduate students will be involved in research both directly through year long senior research projects and indirectly through the Engineering and Public Policy project courses. Finally, the development of environmental modules through the Environment Across the Curriculum program of Carnegie Mellon University will contribute to the environmental education of all engineers.