Development of Critical Data for Predicting Growth of Secondary Organic Aerosols in Air

该项目由一系列研究组成，以测量各种气相前体氧化形成的二次有机气溶胶（SOA）上半挥发性有机化合物（SVOC）的吸收系数。这些调查的理由是，SOA的增长是更好地描述了一个动力学限制机制比一个基于平衡相分配，并吸收系数为各种SVOC对典型的大气SOA，以更准确地模拟SOA的增长。然而，SOA的吸收系数数据是有限的。因此，有关活动包括研究在大容量、慢速流动的气溶胶流管内，硝酸根或/和臭氧氧化SOA前体物所形成的SOA的生成和组成;研究SOA对有机硝酸盐和SVOC的吸收，以及使用衰减全反射傅里叶变换红外光谱法研究SOA成分的可能蒸发（ATR-FTIR）;使用Knudson池和涂覆壁快速流动反应器测量SOA上有机硝酸盐和SVOC的绝对吸收系数;表征自组装单分子膜上有机硝酸盐和SVOC的吸收;以及使用纳米二次离子质谱（nano-SIMS）分析SOA。这项研究将产生重要的信息，在评估SOA增长中动力学限制机制与平衡分配的相对重要性。更广泛的影响包括提供动力学数据和分子对二次有机气溶胶吸收半挥发性有机化合物的见解，通过出版物，暑期教师研讨会，学生和公众的实验室图尔斯参观，研究人员对当地学校的访问，本科生和研究生以及博士后研究员的培训，代表性不足的群体继续参与主要研究者的研究活动，以及为加州大学欧文分校的本科课程开发新的实验。

This project is comprised of a series of studies to measure the uptake coefficients for semi-volatile organic compounds (SVOC) on secondary organic aerosols (SOA) formed from the oxidation of a variety of gas phase precursors. The rationale for these investigations is that SOA growth is better described by a kinetically limited mechanism than one based on equilibrium phase partitioning, and that uptake coefficients for various SVOC on typical atmospheric SOA are needed in order to model SOA growth more accurately. However, uptake coefficients data on SOA are limited. The activities therefore include studies of the generation and composition of SOA formed from oxidation of SOA precursors by nitrate radical or/and ozone inside a large-volume, slow-flow aerosol flow tube; studies of the uptake of organic nitrates and SVOC on SOA as well as studies of possible evaporation of SOA components using attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR); measurements of absolute uptake coefficients of organic nitrates and SVOC on SOA using a Knudson cell and a coated wall fast flow reactor; characterization of the uptake of organic nitrates and SVOC on self-assembled monolayers; and analysis of SOA using nano-secondary ion mass spectrometry (nano-SIMS). The research will yield information important in assessing the relative importance of kinetically limited mechanisms versus equilibrium partitioning in SOA growth.Broader impacts include providing kinetic data and molecular insights on the uptake of semi-volatile organic compounds onto secondary organic aerosol, disseminating results broadly through publications, summer teacher workshops, hosted lab tours for students and the general public, visits of researchers to local schools, training of undergraduate and graduate students and postdoctoral fellows, continued involvement of underrepresented groups in the principal investigator's research activities, and development of new experiments for the undergraduate curriculum at UC-Irvine.