Atmospheric concentrations of PAHs, their possible sources and gas-to-particle partitioning at a residential site of Bursa, Turkey

Atmospheric PAH concentrations were determined in Gulbahce district of Bursa, Turkey between August 2004 and April 2005. Measured PAH concentrations were classified as heating and non-heating season samples. The concentrations of total PAHs in heating season were almost ten times higher than those in non-heating season. Diagnostic ratios and factor analysis results show that in the heating season traffic along with residential heating emissions heavily influence PAH concentrations. The plot of logK, versus logP(L)(0) for all the data set of heating and non-heating season samples gave significantly different slopes. The slope for the heating season samples (-0.92) was steeper than the one for the non-heating season samples (-0.78). The partitioning results for individual samples further indicated that slope values varied depending on air parcel trajectories. Air parcels traveled over water (either over the Black Sea or Aegean Sea) prior to arriving at the sampling site had less steep slopes. Partitioning of PAHs was also investigated by comparing experimentally determined K-p values with the results obtained both from octanol-based model (K-p(Oct.)) and soot and octanol-based model (K-p (Soot+Oct.)). Both models were useful in predicting the experimental K-p values. However, they did not explain the observed variability in the experimental K-p values

Measurement of atmospheric deposition of polychlorinated biphenyls and their dry deposition velocities in an urban/industrial site in Turkey

Dry deposition fluxes and total (gas+particle) concentrations of polychlorinated biphenyls (PCBs) were measured between August 2004 and May 2005. Samples were collected from an urban-industrial site of Bursa, Turkey. A stainless steel pot and a high volume air sampler (HVAS) were employed to collect deposition and ambient air samples, respectively. The dry deposition fluxes of PCBs ranged from 3600 to 56,000 pg m(-2) d(-1) while the total PCB concentrations collected simultaneously were between 35 and 348 pg m(-3). The average dry deposition flux value was in line with the previously reported values. Possible variations in PCB fluxes were likely due to PCB and total suspended particle (TSP) concentrations, and meteorological conditions. No seasonal trends were observed for the bulk deposition samples. The 3- and 4- chlorobiphenyls (CBs) were abundant homolog groups in bulk and concentration samples with ratios of 67% and 90%, respectively. Apparent bulk deposition velocities were calculated by dividing the dry deposition flux value by particle phase air concentration values of PCBs measured with HVAS. The calculated apparent dry deposition velocities ranged from 0.23 cm s(-1) to 3.09 cm s(-1) (aver +/- SD, 0.74 +/- 0.23 cm s(-1))

Dry deposition fluxes and velocities of polychlorinated biphenyls (PCBs) associated with particles

The interest in atmospheric deposition by the scientific community has increased a great deal over the past several years because of its significant contribution to the pollution budget of many natural waters. Dry deposition is an effective removal mechanism for polychlorinated biphenyls (PCBs) from the atmosphere. This study focuses on the understanding of the particulate dry deposition of PCBs in urban areas. In this paper, 43 chromatographic PCB congener peaks which represent 50 individual or coeluting congeners were evaluated. The PCB dry deposition fluxes were measured using a smooth, greased, knife-edge surrogate surface holding greased Mylar strips in Chicago, IL. The average PCB dry deposition flux measured (190±80ngm-2day -1) was similar to those measured in other urban areas. Ambient air samples were also collected simultaneously with flux samples. The average apparent dry deposition velocity, calculated by dividing the fluxes to the particle phase concentrations was 5.2±2.9cms-1. This value is in good agreement with the values calculated using similar techniques