PM10 samples were collected in the area of Megalopolis City (Southern Greece) located in the vicinity of two lignite-fired power plants during an one-year long period (April 2009–March 2010). The samples were analysed for their BC and elemental concentrations (Ca, Fe, Ti, Mn, Cu, Zn, As, K, Cr, Ni) using a smoke reflectrometer and ED-XRF, respectively. The average PM10 concentration was 21.6 ± 10 μg/m3, while that of BC was 1.05 ± 0.55 μg/m3. The concentrations of all the elements, except that of K, were significantly higher in the warm period compared to the cold period of the year, whereas the BC results presented the opposite trend. No statistically significant differences were found between mean PM10 mass concentrations during the warm and cold periods. Source identification was attempted by EF calculations and by Condition Probability Function analysis relating the elemental concentrations to wind directions. The results show that soil/road dust re-suspension from opencast mines and unpaved roads, emissions from vehicle exhausts and mining activities, lignite combustion in the lignite-fired power plants and biomass burning, are the main sources of PM10 in the air over Megalopolis City.