Quantifying the Effect of Vapor Wall Deposition on Chamber-Derived Yields of Secondary Organic Aerosol

本研究的重点是研究二次有机气溶胶（SOA），非常小的颗粒从气相冷凝，在环境室和气体和颗粒沉积到室壁上的影响。模拟研究通常利用来自环境室的基本数据来预测大气中的环境气溶胶浓度。 目前，SOA的模型预测和大气测量之间存在差异。 历史室实验的重新分析表明，以前报告的SOA产量可能被低估。 本研究的主要工作包括：（1）测量了有机物在聚四氟乙烯（Teflon）容器壁上的沉积速率，并将其与有机物的分子特性进行了关联;（2）用各种重要的生物和人为挥发性有机化合物进行的室内实验，其中调节了蒸气向颗粒和壁之间的竞争;以及（3）开发一个综合的燃烧室蒸汽动力学模型，该模型允许从关于蒸汽壁沉积的影响的各个物种的数据进行定量评估，并外推到大气“无壁”条件。

This research is focused on the study of secondary organic aerosol (SOA), very small particles condensed from the gas phase, in environmental chambers and the effects of gas and particle deposition onto the chamber walls. Modeling studies generally utilize fundamental data from environmental chambers in predicting ambient aerosol concentrations in the atmosphere. Currently a discrepancy exists between model predictions and atmospheric measurements of SOA. The reanalysis of historical chamber experiments indicates that prior reported SOA yields may have been underpredicted. The information from this research is critical for understanding aerosol-induced health effects and contributions to global aerosol radiative forcing.The proposed work includes: (1) Measurements of the wall deposition rates of individual organic species on the Teflon walls of a chamber and correlation of those rates to molecular properties of the species; (2) Chamber experiments with a wide range of important biogenic and anthropogenic volatile organic compounds in which the competition between vapor transport to particles and the walls is modulated; and (3) Development of a comprehensive model of chamber vapor dynamics that allows quantitative assessment from data on individual species of the impact of vapor wall deposition and extrapolation to atmospheric "wall-less" conditions.