Determination of ambient elementel and organic carbon concentrations in urban and suburban atmospheres in ankara: estimation of secondary organic aerosol

The concentrations of organic carbon (OC), elementel carbon (EC) and secondary organic aerosol (SOA) in atmospheric particles were investigated at two sites in Ankara, Turkey. The results show that, mean values of EC, OC, SOA for urban station are 2.30, 10.44 and 13.59 μg/m3 respectively; the mean values of EC, OC, SOA for the suburban station were recorded as 0.85, 5.40 and 7.49 μg/m3 respectively. The summer and winter values of the EC concentration in the urban station were found to be 2.17, 2.48 μg/m3 , and 0.72, 1.04 μg/m3 in suburban station. Looking at the monthly changes, the EC values for October, November, December and October, November, December and January for urban station are higher than the EC values obtained for the other months. OC concentrations were also found to be higher in winter than in EC concentrations. When the weekend and weekday EC-OC distributions were examined, it was observed that the concentrations measured during the weekday were higher in both stations. According to the results obtained using the EC tracer approach, approximately 21% of the PM2.5 concentrations measured at the urban station can be defined as secondary organic aerosol. It is also seen that the secondary value of OC is about 12% of the total PM2.5. In suburban station, approximately 17% of the measured PM2.5 concentrations can be identified as secondary organic aerosol and secondary OC concentration is found to account for approximately 8% of the total PM2.5