Aerosol Chemical Mass Closure in Athens, Greece: Towards a Better Understanding of the Seasonal Variation of Aerosol Sources in the Area

This study examines the chemical composition of aerosols over Athens. To achieve this, particulate matter sampling has been conducted on a 6–24 h basis from January 2013 until now. More than 700 aerosol samples were collected at downtown Athens, in Thissio and after mass quantification, were analyzed for major ions (Cl−, Br−, \( {\text{NO}}_{3}^{ - } \), \( {\text{SO}}_{4}^{2 - } \), \( {\text{PO}}_{4}^{ - 3 } \), \( {\text{C}}_{2} {\text{O}}_{4}^{ - 2 } \), \( {\text{NH}}_{4}^{ + } \), K+, Na+, Mg2+, Ca2+), trace elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, V, Zn, Mn, Ni, Pb, P, S, Sb), organic carbon (OC) and elemental carbon (EC). Aerosol chemical mass closure calculations indicated that carbonaceous aerosol constitutes a major component, along with nitrate and sulfate anions, dust, cations and EC. Principal component analysis (PCA) was also applied to better constrain the aerosol sources over Athens with specific emphasis during the winter time, period characterized by intense biomass burning.