AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Developing an Online System for Measuring the Oxidative Potential of Ambient Particles Based on Dithiothreitol (DTT) Assay
JOSEPH PUTHUSSERY, Vishal Verma, University of Illinois Urbana-Champaign
Abstract Number: 450 Working Group: Linking Aerosol Oxidative Potential with Chemical Composition and Biological Endpoints
Abstract Exposure to ambient particulate matter (PM) is known to have an adverse effect on human health. One hypothesized mechanism by which PM affects human health is by inducing the oxidative stress, which can lead to cell damage. Measuring this oxidative stress induced by ambient PM would help in further improving the associations between PM and health impacts, compared to the commonly used PM mass concentrations.
In this study, an online system for measuring the oxidative potential of ambient PM was developed using a mist chamber coupled to an automated analytical system. The system collects ambient particles mainly by two mechanisms: a) continuous washing of the particles attached on to the filter by the mist spray, b) scrubbing of the soluble gases and particulate matter from the sampled air by the mist formed inside the chamber. The extraction solvent, after a specific sampling duration, is removed from the chamber and analyzed using an automated instrument, based on the dithiothreitol (DTT) assay to quantify the oxidative potential of the sampled PM.
Unlike conventional filter based air sampling, the online system has shorter sampling duration and lesser sampling artifacts, especially when measuring the reactive components in the ambient air. The results from the online system correlated well with conventional filter extraction method using both deionized water and methanol. The diurnal trend in the oxidative potential of ambient PM was also determined on an hourly resolution. Overall, mist chamber sampling method appears to be a better alternative to the conventional filter based sampling for measuring the oxidative potential of ambient PM.