Diel Formation and Oxidative Aging of Secondary Organic Aerosol Generated from Phenol Using a Combined Smog Chamber and Oxidation Flow Reactor Approach

DAVID PANDO, Bin Bai, Chase Glenn, Andrew Lambe, Pengfei Liu, Nga Lee Ng, Georgia Institute of Technology

     Abstract Number: 194
     Working Group: Urban Aerosols

Abstract
Secondary organic aerosols (SOA) have long been an integral component of air pollution studies and have been widely characterized in different laboratory settings. After the initial formation, the SOA aging process involves a series of chemical and physical transformations that can significantly alter their composition, size, and properties. However, resulting complexities from the formation of multi-generation products and their continued aging are not well elucidated, and most laboratory SOA studies to date have restricted their focus to hydroxyl (OH) or nitrate (NO₃) radical-initiated aging without considering the effects of diel aging that occurs in the atmosphere. In this work, a novel setup combining an integrated Georgia Tech Environmental Chamber (GTEC) and oxidation flow reactor (OFR) is used to investigate the influence of diel aging on SOA generated from OH or NO₃ oxidation of phenol in the GTEC followed by NO₃ or OH oxidation of phenol and its oxidation products in the OFR. This combination setup allows for the characterization of multi-generation gas-phase products and SOA composition as a function of aging time and mechanism. Phenol and its oxidation products are monitored by a suite of on-line instruments such as gas chromatograph with a flame ionization detector (GC-FID), scanning mobility particle sizer (SMPS), Filter Inlet for Gases and Aerosols coupled to a chemical ionization mass spectrometer (FIGAERO-CIMS), Vocus proton transfer-reaction mass spectrometer, and aerosol mass spectrometer (AMS).