Chemical Speciation of Ultrafine, Fine and Coarse Particulate Matters: Relationship with the Capacity to Generate Reactive Oxygen Species (ROS) and, Cytotoxic and Pro-inflammatory Cellular Response

NEERAJ RASTOGI (1), Umme Akhtar (1, 2), Rob McWhinney (3), Mike Fila (4), Bruce Urch (4), Greg Evans (1), Jeremy Scott (2), Jonathan Abbatt (3)

(1) Southern Ontario Centre for Atmospheric Aerosol Research, University of Toronto (2) Department of Medicine, University of Toronto (3) Department of Chemistry, University of Toronto (4) Gage Occupational and Environmental Health Unit, University of Toronto

     Abstract Number: 461
     Last modified: May 12, 2010

Abstract
Epidemiological studies have increasingly recognized that ambient particulate matter (PM) adversely affect human health. Although particle number, size and composition are shown to be important parameters in toxicology, their relative importance is unclear. For PM effects on health, the main mechanism proposed in the literature is that PM generates reactive oxygen species (ROS) at target sites in the lungs, and affects the cells.
To further elucidate the relationship between physicochemical characteristics of PM and adverse health effects, an intensive field campaign ‘Health Effects of Aerosols in Toronto (HEAT)’ was carried out during February-March, 2010, at the site located on a busy street in downtown Toronto, Canada. Ambient particles were concentrated into three different size ranges, quasi-ultrafine PM (<0.2 micro-meter), fine PM (0.1-2.5 micro-meter), and coarse PM (2.5-10 micro-meter), based on their aerodynamic diameters, using high volume particle concentrators. Ultrafine, fine and coarse PM were collected in triplicates on 47 mm quartz, 47 mm teflon, and 37 mm teflon filters. Sized PM on quartz filters were analyzed for various inorganic and organic chemical species (anions, cations, water- and acid-soluble metals, water-soluble organic carbon (WSOC), elemental carbon, organic carbon, and polycyclic aromatic hydrocarbons (PAHs)) using standard techniques. Teflon filters (47 mm) were analyzed for ROS production capacity of sized PM using dithiothreitol (DTT) assay. Sized PM on 37 mm teflon filters were used for investigating the cytotoxic and inflammatory response (using MTT and ELISA assay, respectively) of human airway epithelial cells (A549) exposed in vitro. Relationships of sized PM with their ROS production capability and toxicity were investigated with respect to their chemical speciation. Important results from this study will be presented.