Factors affecting particle number size distributions at a suburban and a rural site at the Anatolian Plateau

In this work, number size distributions of particles between 0.2 and 34 ??m were measured with a laser spectrometer. Temporal and spatial variability in size distributions were investigated. Measurements were carried out at two stations; the Mediterranean coast of Turkey (Marmaris) and central Anatolia (Ankara). PM1, PM2.5, and PM10 mass concentrations were measured. Flow climatology indicated that air masses spent more time in the south of Mediterranean basin in winter and in the North of the basin during summer months. Median PM10 concentrations measured in Marmaris and Ankara stations were 17 and 38 ??g m??? 3, respectively. North African dust transport was not the main PM10 source in the suburban station, but it was significant in the rural station. The median PM2.5 concentration was higher at Ankara due to anthropogenic emissions which was not observed in Marmaris. Median PM1 concentrations were comparable in both stations. 90-95% of the particles were between 0.26 and 0.42 ??m size ranges. Coarse particle concentrations were higher at the suburban station, whereas fine particles were higher at the rural station. Concentrations depicted a well-defined seasonal pattern in the rural station, with higher concentrations in summer season. Although concentrations of PM size fractions were also higher in the summer season in Ankara station, seasonal differences were not as well-defined as in the rural station. PM1 and PM2.5 concentrations did not show any difference between weekends and weekdays, but PM10 concentrations, particularly the 2.5 ??m < D < 10 ??m, were higher on weekdays due to contribution of resuspended road dust.