Grantee Research Project Results

The Chemical Properties of PM and their Toxicological Implications

EPA Grant Number: R832413C003
Subproject: this is subproject number 003 , established and managed by the Center Director under grant R832413
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Southern California Particle Center
Center Director: Froines, John R.
Title: The Chemical Properties of PM and their Toxicological Implications
Investigators: Cho, Arthur K. , Froines, John R. , Harkema, Jack , Fukuto, Jon , Kumagai, Yoshito
Institution: University of California - Los Angeles , University of Tsukuba , Michigan State University
Current Institution: University of California - Los Angeles , Michigan State University , University of Tsukuba
EPA Project Officer: Chung, Serena
Project Period: October 1, 2005 through September 30, 2010 (Extended to September 30, 2012)
RFA: Particulate Matter Research Centers (2004) RFA Text | Recipients Lists
Research Category: Human Health , Air

Objective:

The overall objectives of Project 3 are: to characterize ambient particulate matter (PM) samples from a variety of PM sources collected in Project 1 according to their potential to induce redox chemistry and oxidative stress in biological tissues; to apply new measures of PM exposure that determine redox activity and thiol depletion; to study particle matrix and size effects on the cellular uptake, intracellular disposition, and biotransformation of particles and selected adsorbed components; and to characterize chemical interactions in PM with respect to reactivity and cellular effects. The central hypothesis of this project is that many adverse health effects associated with PM exposure derive from the induction of oxidative stress, caused by reactive oxygen species generation or the depletion of thiols. Our previous studies have focused on the chemical basis for these actions, i.e., the chemical reactivities of PM that could cause these processes. We have developed a redox assay that determines the catalytic capacity of PM to generate superoxide and have used it to characterize PM from different sources throughout the Los Angeles Basin (LAB).

Approach:

In the next phase of this research, we plan to apply the redox assay and two other chemical assays, one of which determines the reaction with thiols, to assess differences in chemical reactivity among major source types, season and size fraction in PM samples from the LAB. These differences will be analyzed in terms of the chemical constituents found in Project 1 and used to interpret the toxicological findings from Projects 2 and 4. We shall investigate the quantitative relationship between ROS chemistry and intracellular measures of oxidative stress and cellular toxicity. In a second component of the Project, we will study the interaction between carbon black particles and various adsorbed compounds to determine the effect of the particle matrix on chemical and biological activity. These studies are based on our observations that demonstrate residual redox activity in diesel exhaust particles after extractions and those of others showing differences in cellular toxicity of organic compounds when they are adsorbed onto particles. We will thus establish an experimental system of carbon black particles of varying dimensions to which selected organic and inorganic species are adsorbed. The chemical and biological properties of the particles will be determined and the effects of the matrix on the actions of the adsorbed species will be assessed.

Expected Results:

This Project will characterize ambient PM samples from key sources according to their reactivity in redox and electrophilicity assays, and in association with toxicological findings, will provide a basis for identifying PM of the greatest concern for public health in terms of potential to induce oxidative stress and related health effects.

Publications and Presentations:

Publications have been submitted on this subproject: View all 47 publications for this subproject | View all 241 publications for this center

Journal Articles:

Journal Articles have been submitted on this subproject: View all 27 journal articles for this subproject | View all 157 journal articles for this center

Supplemental Keywords:

Bioavailability, metabolism, chemicals, oxidation-reduction, biochemistry, ambient air, particulate matter, oxidative stress,, RFA, Health, Scientific Discipline, Air, particulate matter, Health Risk Assessment, Risk Assessments, Biochemistry, Ecology and Ecosystems, atmospheric particulate matter, particulates, chemical assys, particle matrix, human health effects, PM 2.5, chemical characteristics, toxicology, airway disease, airborne particulate matter, cardiovascular vulnerability, air pollution, human exposure, vascular dysfunction, cardiovascular disease, human health risk

Progress and Final Reports:

Main Center Abstract and Reports:

R832413 Southern California Particle Center

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R832413C001 Contribution of Primary and Secondary PM Sources to Exposure & Evaluation of Their Relative Toxicity
R832413C002 Project 2: The Role of Oxidative Stress in PM-induced Adverse Health Effects
R832413C003 The Chemical Properties of PM and their Toxicological Implications
R832413C004 Oxidative Stress Responses to PM Exposure in Elderly Individuals With Coronary Heart Disease
R832413C005 Ultrafine Particles on and Near Freeways

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.