ARB Research Seminar

This page updated August 3, 2016

Probing the Intrinsic Ability of Particles to Generate Reactive Oxygen Species and the Effect of Physiologically Relevant Solutes

Photo of Suzanne Paulson

Suzanne Paulson

Photo of Cort Anastasio

Cort Anastasio

Photo of Alam Hasson

Alam Hasson

Suzanne Paulson, Ph.D., Professor, Department of Atmospheric & Oceanic Sciences and Director of UCLA Center for Clean Air, University of California, Los Angeles; Cort Anastasio, Ph.D., Professor and Vice Chair, Department of Land, Air & Water Resources, University of California, Davis; Alam Hasson, Ph.D., Professor and Chair, Department of Chemistry, California State University, Fresno

September 01, 2016
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


Oxidative stress mediated by reactive oxygen species (ROS) is a leading hypothesis for the mechanism by which particulate pollution contributes to a range of illnesses, including asthma and cardiovascular mortality. The goal of this study was to understand the components in particles responsible for ROS formation under physiological conditions. The investigators conducted a field campaigns in the South Coast Air Basin, aimed at capturing photochemical smog; and in Fresno, which has significant contributions from biomass burning. Samples were extracted in simulated lung fluid, and analyzed for their ability to generate ROS such as hydrogen peroxide (H₂O₂) and hydroxyl radical (.OH) and to consume dithiothreitol (DTT) The contributions of transition metals and quinones to ROS formation was also investigated.

Normalized to mass, H₂O₂ production was much higher in the Fresno samples, while both .OH and DTT consumption were nearly identical in the Fresno and Claremont samples. The Claremont samples have relationships that are qualitatively consistent with laboratory results, which found that copper and selected quinones can all generate significant amounts of OH and H₂O₂, while iron can generate .OH but not H₂O₂. In contrast to Claremont, the mass of biomass burning HULIS was by far the dominant variable in all multivariate regressions for the Fresno samples. In several cases, it was the only variable with a significant correlation, although dependencies on the transition metals iron and copper and iron were evident in some cases.

The results indicate dominant roles for soluble copper, iron and manganese, and also biomass burning aerosol (where present) in the production of ROS from particulate matter (PM) samples in simulated lung fluid. This study furthers the understanding of how ROS are formed from PM as well as the possible chemical components and source types that may be responsible for increased ROS production.

Speaker Biography

Suzanne Paulson, Ph.D., is Professor in the Department of Atmospheric & Oceanic Sciences and the Director of the UCLA Center for Clean Air, University of California, Los Angeles. Dr. Paulson's current research includes the contribution of the buildings and other features of the built environment on spatial distributions in complex urban environments. Professor Paulson and her students are also working to link the chemical composition of particles with production of reactive species believed to underlie the inflammatory responses caused by inhalation of particulate matter. Professor Paulson earned a B.A. in Chemistry from the University of Colorado, and a PhD in Environmental Engineering Science from the California Institute of Technology.rsors.

Cort Anastasio, Ph.D., is Professor and Vice Chair in the Department of Land, Air & Water Resources at University of California, Davis. Dr. Anastasio's research focuses on oxidant generation by particles as well as the chemistry and photochemistry in cloud and fog drops, aerosol particles, and snow. For over a decade, Professor Anastasio's research group has been examining the ability of airborne particles to generate reactive oxygen species (ROS), a process that has been linked to the adverse health effects of PM. In addition to measuring ROS from ambient and laboratory particles, his group has also developed a technique to quantify the contributions of individual metals and quinones to ROS formation from particles. Dr. Anastasio serves as a member of the Scientific Review Panel on Toxic Air Contaminants for the State of California.

Alam Hasson, Ph.D., is a Professor of Chemistry and Chair of the Department of Chemistry at California State University, Fresno. Dr. Hasson's research group has been involved in measurements of quinones and reactive oxygen species generation in ambient particulate matter for a number of years. Professor Hasson earned his B.A. degree in Chemistry from the University of Oxford and his Ph.D. in Physical Chemistry from the University of Birmingham. He then worked as a postdoctoral researcher at UCLA for three years before joining the Chemistry department at California State University, Fresno in 2001.

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