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Ambient Particulate Matter Oxidative Potential: Chemical Determinants, Associated Health Effects, and Strategies for Risk Management
DONG GAO, Susannah Ripley, Scott Weichenthal, Krystal Godri Pollitt, Yale University
Abstract Number: 590
Working Group: Health-Related Aerosols
Abstract
Exposure to ambient air pollution has an adverse influence on human health. There is increasing evidence that oxidative potential (OP), the capacity of airborne pollutants to oxidize target molecules by generating redox oxidizing species, is a plausible metric for particulate matter (PM) toxicity. Several acellular techniques have been used to measure OP (respiratory tract lining fluid, dithiothreitol, ascorbic acid, and electron paramagnetic resonance assays). We will present a meta-analysis of the PM chemical constituents that have been identified to drive the OP response. We further discuss the epidemiologic literature to identify studies that reported an association between exposure to ambient PM and a health outcome in a human population, and in which exposure was measured by both PM mass concentration and OP. Laboratory studies have shown that specific redox-active metals and quinones are able to contribute OP directly. However, interactions among PM species may alter the redox properties of PM components. In ambient PM measurements, all OP assays were found to be correlated with metals (Fe, Cu) and organic species (photochemically aged organics). Across the epidemiological studies reviewed, associations between fine PM (PM2.5) mass and cardio-respiratory outcomes were found to be stronger at elevated OP levels but findings varied across the different OP measurement techniques. Future work should aim to identify specific situations in which PM OP can improve air pollution exposure assessment and/or risk management. This may be particularly useful in countries with low PM2.5 mass concentrations over broad spatial scales where such information may greatly improve the efficiency of risk management activities.