Determination of chemical composition of pm10 samples collected at two different stations in Bolu

Daily PM10 samples were collected at a semi-urban site (AIBU campus) during April 2013 and day and night samples were collected at an urban site (city center) during May and October 2013. Sample collection scheme allows us to compare the sites, seasons and diurnal variation of PM10 components. The collected samples were analysed in terms of elemental carbon (EC), organic carbon (OC) and major ions (Ca2+, Mg2+, K+, NH4+, Na+, SO42-, NO3-, Cl-, and PO43-). Meteorological variables, SO2 and PM10 were also determined with the concurrent measurements at the urban site. A filter holder with two (front and back) pre-fired quartz fibre filters in series was employed to collect PM10 samples. Sampler was mounted on the roof, which is 14 m height in the semi-urban site while it was placed 1.6 m above the ground level at the rural site. The average mass concentration of PM10 was 29±14 µg m-3at the AIBU campus while it was measured at87 ± 40 µg m-3and 72 ± 62 µg m-3in May and October, respectively, at the city center. EC and OC contents of the collected samples were determined using the Sunset Lab EC/OC analyser. The average EC and OC concentrations were found as 0.98±0.60 and 4.27±2.47 µg m-3 at the AIBU campus, respectively. The contribution of measured variables to PM10 mass in terms of seasons was also evaluated. It was found that contribution of OC to PM10 mass an increased in autumn, which was attributed to increase in coal combustion due to coldweather. Contributionof secondary inorganic ions namely, SO42- ve NO3-, to PM10 mass decreased toward autumn, which was explained by the decreased photochemistry that enhanced the production of these anions during the summer season. Another striking in this study is that contribution of NH4+ to PM10 mass increased in the autumn, which implies that dried cow dung is still being used for domestic heating purposes in cold season. It was also found that PM10 mass measured at the city center is about 2.5 times higher than the value recorded at the campus site. Lastly, EC tracer method was applied to the generated data set to find the POC and SOC fractions of the determined OC. It was obtained that contribution of SOC to OC total mass was higher in those samples collected during day time and also at the city center.