Ionic composition of PM10 in the area of Thessaloniki, Greece

Airborne particulate matter (PM10) was collected from July 1997 to July 1998 at three locations in the city of Thessaloniki. PM10 samples were analyzed for Cl−, NO3−, SO42−, Ca2+, Mg2+, Na+, K+ and NH4+. The average PM10 concentrations were found similar in all three sites with higher values in cold period. The ionic content comprised the 17–23% of the PM10 mass and sulfate made up the 35–38% of the PM10 ionic content with an average concentration of 4.80–7.26 μg m−3. Good correlation was found for SO42− and NO3− with Ca2+, Mg2+ and Cl−. Two factors were found to influence the variance of ionic constituents in PM10 by using factor analysis. Data evaluation considering wind direction showed that higher PM10 and other ionic concentrations are associated with calm conditions, suggesting influences of local sources.