AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Complexation State of Metals in Ambient Particulate Matter (PM) and Its Effect on the Oxidative Potential
JINLAI WEI, Vishal Verma, University of Illinois Urbana-Champaign, Urbana IL
Abstract Number: 453 Working Group: Linking Aerosol Oxidative Potential with Chemical Composition and Biological Endpoints
Abstract Transition metals have long been recognized as an important component contributing to the toxicological property of ambient particulate matter (PM). One method of assessing this toxicity is to measure the capability of PM components to generate reactive oxygen species (ROS). However, whether transition metals are complexed with organic compounds or free in ambient PM, which could be an important factor determining their capability to generate ROS, is not well understood. We target to investigate the complexation states of important atmospheric metals in this study. A novel fractionation scheme is developed to separate metals from ambient PM into hydrophilic, hydrophobic and free fractions. The scheme has been validated by applying it on a mixture of Suwannee River fulvic acid (SRFA) and Fe. SRFA is selected as a model compound as it represents the humic-like substances present in ambient PM, which are believed to be complexed with Fe. The preliminary results show that a significant amount of iron pre-mixed with SRFA is detected in both hydrophobic and hydrophilic fractions, indicating potential complexation with both types of organic substances. Similar tests conducted with the ambient PM show up to 60%-80% of iron complexed with organic compounds. The experiments to assess the impact of complexation on the ROS generation capability of metals are underway and would be discussed in this talk.