AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Source Apportionment of the Redox Activity of Urban Quasi-ultrafine Particles (PM0.49) in Thessaloniki Following the Increased Biomass Burning due to the Economic Crisis in Greece
Georgios Argyropoulos, Athanasios Besis, Dimitra Voutsa, Constantini Samara, Mohammad Sowlat, SINA HASHEMINASSAB, Constantinos Sioutas, Aristotle University of Thessaloniki
Abstract Number: 211 Working Group: Health Related Aerosols
Abstract The goal of this study was to explore the sources driving the oxidative potential of ambient quasi-ultrafine particulate matter (PM0.49, particles with an aerodynamic diameter below 0.49 micro-meter) in the city of Thessaloniki, Greece’s second largest city and one of the most polluted cities of European Union (EU). Twenty 48-hr PM0.49 samples were collected in one urban traffic (UT) site and one urban background (UB) site in two separate seasons (i.e., cold and warm). The chemical composition and the oxidative potential (measured by the dithiothreitol (DTT) assay) of the collected particles were subsequently measured. Two different approaches were employed to link the measured redox activity of PM0.49 with specific sources: (a) Principal Component Analysis of the chemical components of PM0.49 followed by Multilinear Regression analysis of the measured redox activity on factor tracers (PCA-MLR), and (b) Robotic Chemical Mass Balance receptor modelling of the ambient PM0.49 mass followed by MLR of the redox activity on the determined source contributions (RCMB-MLR). In the urban traffic (UT) and urban background (UB) sites, DTT activity was highly correlated with EC and levoglucosan , respectively. This suggests that biomass burning (represented by levoglucosan) is the main driver of the DTT redox activity in the urban background (UB) site, while DTT redox activity of the PM0.49 particles is mostly driven by vehicular emissions (as represented by EC) in the urban traffic (UT) site. In addition, both per-mass and per-volume DTT redox activity of the PM0.49 particles were found to be substantially higher in the urban background (UB) site in the cold season. This finding underscores the increase in PM toxicity with the shift from traditional oil burning to biomass burning for residential heating, a result of the dramatic rise in the price of fuel oil following the economic crisis in Greece.