AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Oxidative Potential of Various Laboratory-generated PM from Biomass Burning, Coal Burning, Fuel Combustion, and Road Dust
LUCILLE JOANNA BORLAZA, Seojong Kim, Minhan Park, Kwangyul Lee, HungSoo Joo, Kihong Park, Gwangju Institute of Science and Technology
Abstract Number: 706 Working Group: Health Related Aerosols
Abstract Numerous studies have assessed the potential of ambient particulate matter (PM) to generate reactive oxygen species (ROS) via oxidative potential (OP) analysis. But, very limited studies have quantified specific sources of PM and its ROS-generating capability. To address this issue, this study aimed to quantify OP of source-specific PM that are common in ambient particulate matter including biomass burning, coal burning, fuel combustion, and road dust in order to identify PM sources that have higher health impact than the others. Controlled volume chambers and aerosol generating systems were developed for this purpose. Laboratory-generated PM from various sources were collected using URG cyclones at different sampling parameters that closely simulate real-world conditions. Particle size distribution and mass concentration were monitored by coupling an optical particle counter and a scanning mobility particle sizer. Chemical characterization was done by analyzing ions, metals, organic carbon (OC), and elemental carbon (EC) concentrations. Two a-cellular chemical assays were used to characterize OP of water-soluble PM2.5: Dithiothreitol (DTT) and Electron Spin Resonance (ESR) assay. OP-DTT was carried out through assessment of the capability of redox active compounds in PM2.5 to transfer electrons from DTT to oxygen thereby generating superoxides. The consumption of DTT over specific time intervals (5, 15, 25, 35 and 45 mins) was interpreted as a measure of the capability of ambient PM2.5 to produce ROS. On the other hand, OP-ESR was performed using ESR with a spin trap (5,5 – dimethylpyrroline – N – oxide or DMPO) which measures the capability of PM2.5 to generate hydroxyl radicals (•OH) though Fenton type reactions with the presence of hydrogen peroxide. Varying OP, physical, and chemical properties of different PM sizes and sampling conditions will be presented in this study.