PM2.5 BOUND ORGANIC MOLECULAR MARKER SPECIATION METHODS AND OBSERVATIONS FROM DAILY MEASUREMENTS IN ANKARA, TURKEY

In this study PM2.5 samples, for organic speciation, were collected at two location in the city of Ankara. One of these stations is a typical urban station close to the city center and the other one is a suburban station located in the Middle East Technical University campus. The two stations were approximately 15 km apart. Samples were collected onto prebaked quartz filters using a Hi-Vol sampler with a typical flow rate of 1.06-1.18 m(-3) min(-1). Mass concentration was determined gravimetrically by weighting filters before and after sampling. Average PM2.5 mass concentrations were 38 mu g m(-3) and 54 mu g m(-3) at the urban and suburban stations, respectively. 15 Alkanes, 18 PAH, 9 fatty acids and levoglucosan were determined using a GC-MS after fairly exhaustive sample processing. Typical concentrations ranged between 0.9 ng m(-3) and 8.1 ng m(-3) for alkanes, 0.2 ng m(-3) and 0.9 ng m(-3) for PAHs, 0.4 ng m(-3) and 15.1 ng m(-3) for fatty acids. Concentrations of most of the measured organic markers were higher at the urban station compared to suburban one. Typical urban-to-suburban ratio were 1.8 for alkanes, 1.9 for PAHs and 2.0 for fatty acids. Winter time concentrations of measured parameters were generally higher than their concentrations in summer samples. However there were also exceptions to this general trend. For example summer and winter concentrations of fatty acids were comparable in both seasons and summer concentrations of hexadecanoic acid and octadecanoic acids were higher than their corresponding concentrations in winter.