AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Sources and Chemical Processing of Organic Aerosol during the Summer in the Eastern Mediterranean
EVANGELIA KOSTENIDOU, Kalliopi Florou, Christos Kaltsonoudis, Maria Tsiflikiotou, Magdalini Psichoudaki, Spyros Pandis, Institute of Chemical Engineering Sciences, ICE-HT, Greece
Abstract Number: 192 Working Group: Urban Aerosols
Abstract During summer 2012 the concentration and chemical composition of fine aerosol was measured in two Greek cities, Patras (population 300,000) and Athens (population 4 million) in an effort to better understand the chemical processing of particles in the high photochemical activity environment of the Eastern Mediterranean. An Aerodyne High Resolution Aerosol Mass Spectrometer (HR-AMS) was used to measure the size-resolved chemical composition of the non-refractory PM$_1. Additional measurements included those of the aerosol size distribution (SMPS), optical properties (nephelometer and MAAP), gas-phase concentrations (PTR-MS, NO$_x, O$_3, SO$_2, and CO), filter-based composition, etc.
In both sites the levels and composition of PM$_1 levels were surprisingly similar to each other demonstrating the importance of regional sources for the corresponding pollution levels. The PM$_1 average mass concentration was 9-12 micrograms m$^(-3), which is very close to the PM$_1 levels of a remote location in the Mediterranean during summer (e.g. Finokalia). However, the contribution of sulphate in the urban areas was around 37% quite lower than Finokalia’s (55%). Organic aerosol (OA) contributed approximately 45% in both cities.
Positive matrix factorization (PMF) was applied to the high resolution (HR) organic aerosol mass spectra. For Athens 4 sources could be identified: LV-OOA (low volatility oxygenated OA) related to aged OA, SV-OOA (semi-volatile oxygenated OA) a less oxygenated OA, HOA (hydrocarbon-like OA) associated with traffic emissions and COA (cooking OA) related with food preparation. On average the organic matter consisted of 53% LV-OOA, 16% SV-OOA, 15% HOA and 16% COA. In Patras a 3-factor PMF solution was found to describe best the OA AMS: LV-OOA (29%), SV-OOA (53%) and HOA (18%). The organic to carbon (O:C) mass ratio was 0.64 in Patras and 0.58 in Athens. In both cases the aerosol was acid (ratio of cations to anions 0.73±0.07 in Patras and 0.70±0.08 in Athens).