AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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The Oxidative Potential of Gasoline-derived Organic Aerosols and Wood Smoke Particles
HUANHUAN JIANG, Myoseon Jang, University of Florida
Abstract Number: 252 Working Group: Linking Aerosol Oxidative Potential with Chemical Composition and Biological Endpoints
Abstract Human exposure to fine particle matter (PM2.5, aerodynamic diameter < 2.5 µm) has been linked to increased morbidity and mortality from respiratory and cardiovascular diseases. Organic aerosols (OA) formed from the photooxidation of gasoline vapor and wood smoke account for a large fraction of PM2.5. However, the health effects of OA are still unclear due to the complex OA compositions. Among the diverse OA components, quinones, organic hydroperoxides, peroxyacyl nitrates and electron-deficient alkenes, which have been known to induce oxidative stress in biological systems, are valuable to be studied.
Given the dynamic evolution of OA during the photooxidation, it is necessary to investigate the change of compositions and oxidative potential of OA with the increase of aging time. Aged wood smoke particles and gasoline-derived OA were formed in a large outdoor photochemical smog chamber. OA was collected within a small amount of deionized water using a particle-into-liquid sampler. The aqueous OA samples were then applied to a series of chemical assays to quantify the oxidative potential (dithiolthreitol (DTT) assay), the concentrations of organic hydroperoxides (4-nitrophenylboronic acid assay), and peroxyacyl nitrates (Griess assay). A gas chromatograph-mass spectrometer was also applied to characterize the compositions of OA. The preliminary results show that the oxidative potential of both gasoline-derived OA and wood smoke particles decreased with aging, which was associated with the degradation of organic hydroperoxides and quinones.