Concentration and chemical composition of PM2.5 for a one-year period at Thessaloniki, Greece: A comparison between city and port area

The chemical characterization of PM2.5 fraction was studied during a one-year sampling campaign conducted at an urban area (city center) of Thessaloniki, Greece. PM2.5 samples were analyzed for polycyclic aromatic hydrocarbons, minerals and trace elements, water soluble ions, organic and elemental carbon. The average PM2.5 concentration (37.7 μg/m3) was significantly higher than the EU legislated annual limit of 25 μg/m3 underlining the temporal problems of air quality in the city. PM mass and chemical composition data collected at the city center were compared to the corresponding data which were simultaneously collected at a site near the port. The atmosphere in the port area has been found to be more aggravated compared to the city center area. Statistical analysis and diagnostic ratios of the collected chemical data at both sites were used to identify the main sources contributing to the pollutant levels: traffic, biomass burning for domestic heating, shipping and port activities and dust resuspension. In general, chemical analysis highlighted that PM2.5 mass was mainly composed by secondary inorganic aerosols and particulate organic matter, reflecting the simultaneous contribution of both regional and local emission sources.