AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Sources of Reactive Oxygen Species (ROS) Generation Properties of Atmospheric Aerosols in Southeastern United States
VISHAL VERMA, Ting Fang, Laura King, Hongyu Guo, Rodney Weber, Georgia Institute of Technology
Abstract Number: 420 Working Group: Linking Aerosols with Public Health in a Changing World
Abstract ROS generating properties of the ambient aerosols has emerged as a widely accepted mechanism responsible for the various health outcomes associated with particulate matter (PM) pollution. As part of a multi-institutional and collaborative center (Southeastern Center for Air Pollution & Epidemiology) study, we measured the potential of the atmospheric aerosols in southeast US to generate superoxide radicals. Ambient fine particles (Dp< 2.5 micro-meter) were collected on the quartz filters (23 hours integrated samples, N = 500) at multiple (N=7) sites representing different environmental settings from urban to rural environments, for one complete year from May 2012 to April 2013. Detailed chemical analyses including carbonaceous species (elemental and organic carbon, water-soluble organic and brown carbon), inorganic ions and water-soluble metals were conducted on all of the samples, and ROS-generation potential of the particles was measured using dithiothreitol (DTT) assay. The emission sources were identified using linear regression analysis between DTT activity and various chemical components and positive matrix factorization was applied to apportion the relative contribution of these sources in the PM ROS-generation potential. Four major emission sources, i.e. vehicular emissions, road dust resuspension, secondary photochemical formation and biomass burning, are identified significantly contributing to the ROS activity of the particles. The associations of the emissions sources with PM-ROS activity have strong spatial and seasonal trends. Primary vehicular emissions contribute throughout the year particularly in urban areas. In summer, resuspended dust makes a significant contribution in urban sites, but secondary organic aerosols dominate the ROS generation in both urban and rural areas. In winter, biomass burning is the major source contributing to the PM-ROS generation potential throughout southeast. Further statistical and mechanistic studies are underway to delineate the specific chemical components present in each source to drive the ROS responses and the subsequent health effect mechanisms in humans.