AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Application of Aerosol Mass Spectrometry to infer the Sources of the Reactive Oxygen Species Generating Properties of Organic Aerosols in the Southeastern United States
VISHAL VERMA, Ting Fang, Lu Xu, Nga Lee Ng, Rodney Weber, Georgia Institute of Technology
Abstract Number: 455 Working Group: Linking Aerosols with Public Health in a Changing World
Abstract Organic aerosols (OA) comprise a substantial fraction of the particulate mass in ambient atmosphere. Recently many of the bulk organic aerosol species have been associated with the markers of adverse health effects in humans. Mechanistic studies indicate that the reactive oxygen species (ROS) generated by organic aerosols can serve as the starting link for understanding these associations. Certain groups of the organic compounds such as secondary organic aerosols (SOA) and HULIS (Humic-like-substances) have been shown as highly oxidative; however, the specific components responsible for the ROS generation have not yet been identified. As part of a multi-institutional and collaborative center (Southeastern Center for Air Pollution & Epidemiology) study, we investigated the oxidative properties of organic aerosols in the southeastern US, in different seasons of the year when a particular source dominates the mass concentrations. For example, in summer, SOA is the strongest source while biomass burning dominates in winter. ROS-generation properties of these organic fractions were measured using the DTT (dithiothreitol) assay, which measures capability of the particles to generate superoxide radicals. Various factors of the organic aerosols were inferred from aerosol mass spectrometry, i.e. hydrocarbon-like OA (HOA), semi-volatile oxygenated OA (SVOOA), low-volatility OOA (LVOOA), isoprene OA, and biomass burning OA (BBOA). The contribution of each of these factors in the DTT activity of organic aerosols will be assessed using multiple linear regressions and positive matrix factorization tools. Our goal is to identify the specific organic components most responsible for driving the PM ROS generation, to trace their emission sources and to quantify their individual contribution in the aerosol oxidative potential.