Same transportation, extraction, and analysis procedure applied to the real samples were employed to the blanks.The limit of detection (LOD) values were calculated by adding three times standard deviations of the Ivacaftor EC50 blank samples to the average PCB concentrations in the blank samples [23�C26]. LOD values were determined for each PCB congener and data smaller than the LOD values were neglected.The ratio of the average PCB value obtained in the blank samples to the PCB values determined in the samples were found as 5.7 �� 3.5% for GFF, 1.7 �� 1.0% for PUF, 3.0 �� 2.8% for WDDS, and 3.3 �� 3.5% for the BDS. The average recovery efficiencies for the PCB 14, PCB 65, and PCB 166 were shown in Table 2. All results in this study have been reported after surrogate and internal correction.

Table 2Recovery efficiencies for the HVAS and BDS samplers.3. Results and Discussions3.1. Ambient Air ConcentrationsDuring the sampling period, 34 atmospheric air samples were collected by means of the HVAS. Two samples were collected in the first half of the month and the other two were taken in the second half when there was no rain. The average gas and particulate phase PCB concentrations (mean �� SD) were 320 �� 110pg/m3 and 40 �� 30pg/m3, respectively. Total PCB concentration was determined to be 360 �� 100pg/m3 at the YS sampling site. These levels of concentrations were among the high levels determined in urban sites (Table 3) [3, 4, 29, 31]. The high PCB levels suggested that the occurrence of PCBs was due to local sources and long-range transport.

The area of Northwestern Turkey is known as an area with mid to high concentrations of PCBs and many studies have been conducted last years to describe the situation [16�C18, 22, 33]. The most abundant individual congeners, in this study, were PCB-85, PCB-52, and PCB-28 with average concentrations of 23.6, 21.3, 20.8pg/m3, respectively. Regarding the other congeners of the typical seven PCB-mix, they occurred in various concentrations with the following order: PCB-153 < PCB-118Dacomitinib (Figure 2).Figure 2Distribution of the average gas/particulate concentrations of the PCB congeners.Table 3Atmospheric concentrations of PCBs at various locations.The distribution between gas and particulate phase PCB congeners is shown in Figure 2. It can be seen that 90% of the total PCB burden was in the gas phase and lower molecular weight PCBs were more dominant in the collected samples because they partition mainly in the gas phase.