AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Oxidative Potential of Ambient Aerosol in Athens, Greece and its Dependence on Chemical Composition
DESPINA PARASKEVOPOULOU, Aikaterini Bougiatioti, Ting Fang, Eleni Liakakou, Rodney J. Weber, Athanasios Nenes, Nikolaos Mihalopoulos, National Observatory of Athens
Abstract Number: 650 Working Group: Linking Aerosol Oxidative Potential with Chemical Composition and Biological Endpoints
Abstract Airborne particulate matter (PM) has been identified as a major cause of adverse health effects. The ability of PM to catalyze reactive oxygen species generation in vivo and lead to oxidative stress is thought to be correlated with aerosol chemical characteristics. This mechanism of aerosol species to catalytically deplete the antioxidant buffering capacity of cells and/or result in ROS production is called oxidative potential (OP). The variability of OP is studied for the first time in the area of Eastern Mediterranean in conjunction with site, local and regional sources and the age of aerosol. For this purpose, we have used a semi-automated system developed at the Georgia Institute of Technology, which is based on dithiotreitol (DTT) assay. DTT simulates the in vivo transfer of electrons during reduction of O2 to superoxide anion (O2-), caused by the presence of redox-active species in PM. Aerosol toxicity is measured through DTT consumption rate per unit volume of air, called water-soluble “DTT activity”. The present study is conducted from July 2016 to April 2017, at a downtown site of Athens. The daily DTT activity is in the range of 0.02-0.81 (nmol/min)/m3 while, biomass burning organic aerosol (BBOA) presents intrinsic water-soluble DDT activity of 63±6 pmol/min/μg, indicating that water soluble aerosol components possess significant oxidative properties in the studied area. The seasonal variability demonstrates a higher fine aerosol DTT activity during the coldest period of the year, presenting very good correlations with BBOA (r2=0.83) and biomass burning oxidized organic aerosol (OOA-BB) (r2=0.83) during wintertime. The ameliorated winter correlations emphasize on the important association of redox activity with biomass burning activities, since wood burning is widely used for domestic heating during wintertime in Greece, due to the economic recession.