AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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A Comparison of Oxidative Potential of POA and SOA Derived from α-Pinene and Gasoline Engine Exhaust Precursors
Khairallah Atwi, ALAN SHIHADEH, Constantinos Sioutas, Farimah Shirmohammadi, Vishal Verma, James Schauer, American University of Beirut
Abstract Number: 646 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Organic aerosols in the atmosphere are thought to play an important part in the etiology of respiratory and cardiovascular diseases, largely through systemic inflammation and oxidative stress. Secondary organic aerosols represent a major fraction of ambient organic aerosols, however their relative contribution to the inhalation burden of inflammatory and oxidative agents is poorly characterized. In this study we compared the chemical composition (EC/OC, metals, water soluble OC, organics), particle size distributions, and oxidative stress potentials (using DTT and ROS macrophage assays) of raw and oxidized gasoline engine exhaust, and raw and oxidized α-pinene. The SOA was generated using a custom-built oxidation flow reactor, fed either by α-pinene vapors or by 500:1 diluted gasoline engine exhaust. The flow reactor was operated at 22C and 60% RH, and an equivalent atmospheric aging of several days to weeks, resulting in an engine exhaust SOA:POA mass ratio of approximately 100. Comparisons of oxidative stress potential between the various aerosol systems are made both per unit volume of aerosol sampled, and per unit particle mass, and contrasted to previously reported data for ambient air.