AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Reactive Oxygen Species (ROS) Associated with the Ambient Particulate Matter – Insights from Southeastern Center for Air Pollution and Epidemiology (SCAPE) Study
VISHAL VERMA, Ting Fang, Josephine Bates, Robert Devlin, Armistead G. Russell, Rodney J. Weber, Georgia Institute of Technology
Abstract Number: 222 Working Group: Health Related Aerosols
Abstract Ambient particulate matter (PM) exerts adverse health effects by generating reactive oxygen species (ROS) in-vivo. To examine this hypothesis and to delineate the PM components and sources associated with ROS, a multi-institutional campaign was conducted in the southeastern United States. The campaign was part of a joint research project between Georgia Tech and Emory University (SCAPE) that involved PM2.5 sampling at multiple sites in the southeast.
The uniquely large dataset on the ROS activity measured by dithiothreitol (DTT) assay and speciated chemical components allowed the use of receptor modeling techniques, which yielded biomass burning and secondary aerosol formation from vehicular emissions as the major sources contributing to the ROS activity of ambient particles. The specific components present in these sources, which were associated with the ROS activity appear to be large molecular weight aromatics (humic-like substances, called HULIS) and metals (Cu and Mn). Further fractionation of HULIS based on the solubility of its compounds in different solvents of varying polarity indicates that the ROS active organic species are polar in nature, which included oxygenated derivatives of quinones or quinone-type compounds.
The receptor model was then used to estimate historical levels of ROS activity for use in an epidemiologic analysis in Atlanta. ROS activity was more strongly associated with emergency department visits for asthma/wheezing and congestive heart failure than PM2.5 mass. In addition, a study of human subjects to concentrated ambient particles showed ROS was at least as correlated to various observed biological responses as PM2.5 mass. Collectively, these results indicate the importance of both primary vehicular emissions and biomass burning, and products following atmospheric processing, to ROS activity of ambient particles. The results suggest oxidative stress is a biologically plausible mechanism supporting the associations of adverse health outcomes and ambient PM2.5 mass.