Passive samplers have been widely used as a cost-effective and reliable technique in measuring ambient Volatile Organic Compounds (VOCs) concentrations. The main source of uncertainty in environmental applications of passive sampling is the use of uptake rates determined in the laboratory (Tolnai et al., 2000). With the exception of BTX compounds, information on uptake rates of VOCs present in ambient air is limited. In this paper, uptake rates for more than 50 aromatic, olefinic, paraffinic and halogenated organic compounds that may be present in ambient air were determined for different concentration and meteorological conditions by sampling parallel to a an online-GC between, September 2005 and May 2006, at an urban site in the city of Bursa, Turkey.

In this period, hourly VOC concentrations were measured using an HP Gas Chromatograph (GC) with Flame Ionization Detector, equipped with a Deans Switch that was coupled to a Unity Thermal Desorption and Air Server sampling system. The instrument was calibrated to detect 148 VOCs with carbon numbers ranging between C₂ and C₁₂. However, approximately 66 of these were detected during measurements.

Passive sampling tubes are filled with Chromosorb 106 adsorbent. Fifty compounds ranging from C₂ to C₁₂ were detected upon thermal desorbtion and subsequent GC-FID measureement. Data from seven exposure periods are included in this discussion. For each exposure period more than 3 tubes were co-located with online GC inlet. The meteorological data were obtained from the nearest meteorological station, which is approximately 5 km from the measurement point. Data from a total of 49 passive sampling tubes and 1296 hourly active measurements were used to evaluate the effect of meteorology on uptake rates. The mean uncertainty range and the coefficient of variation for each compound were calculated for active and passive sampling. After obtaining uptake rate for each exposure period, influence of meteorological condition on uptake rates was investigated.