Elementel-organic carbon and pah composition of Bolu tunnel atmosphere and road dust

Tunnel air samples were collected by using PUF samplers in the Bolu Mountain Tunnel located on the highway in the axis of Edirne-Istanbul-Ankara on the road network of Turkey; Concentrations of Elemental and Organic Carbons (EC and OC) and particulate and gas phase US-EPA priority polltant PAH compounds were determined at the entrance and the exit of the tunnel. At the end of the study; Emission Factors (EF) were calculated for 16 priority PAH compounds and Elemental Carbon (EC) and Organic Carbon (OC). In order to examine the seasonal changes of emissions, two sampling surveys were performed, namely in summer and winter seasons. The first sampling (winter season) was done between February 24 and March 02, 2014 and the second sampling (summer season) was done between June 02 and June 04, 2014. In addition road dust samples were also collected and analysed for particulate and gas phase PAHs and EC-OC to determine the road dust contributions. OC-EC determinations were performed by using the NIOSH 870 protocol by a Sunset OC-EC analyzer. Particulate and gas phase PAHs were determined by HPLC-DAD after soxhelet extraction technique and celan-up columns. The average OC and EC concentrations measured at the entrance of the tunnel during the winter season were 14.2 ± 12.8 μg/m3 and 16.3 ± 6.83 μg/m3 respectively, at the exit of the tunnel 41.3 ± 15.6 μg/m3 and 68.4 ± 23.1 μg/m3, respectively. In the summer season, average OC and EC concentrations measured at the entrance of the tunnel were 18.1 ± 10.1 μg/m3 and 22.4 ± 8.7 μg/m3, respectively, and at the exit of the tunnel the average concentrations were 63.2 ± 17.9 μg/m3 88.0 ± 27.5 μg/m3, respectively. Furthermore, the contribution of OC to TSP concentrations was 25.1 % ± 7.3 % in winter samples, 24 ± 7.5 % in summer samples. The contribution of EC to TSP was 42 ± 12 % for winter season and 37 ± 12 for summer season. In summer season, the most abundant PAH compounds were phenanthrene, anthracene and pyrene, in winter season the most frequently observed PAH compounds were fluorene, phenanthrene and pyrene. The output of the OC-EC Analyzer system contains four OC peaks and reported as OK1, OK2, OK3 and OK4 depending on the temperature program in the analysis protocol. These OK peaks were associated with the sum of PAH compounds which were classified with respect to their ring numbers. As a result of summer season, the sum of acenaphthene, acenaphthylene, and fluorene appears to have a high correlation (r = 0.85) with OK1 peak. OK2 peak had significant correlation with the sum of phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene and chrysene compounds were investigated and calculated as r=0.85. The sum of benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene and benzo(g,h,i)perylene compounds showed strong correlation with OC3 peak (r = 0.87). As a result; in winter season phenanthrene, fluorene and pyrene were found as the most abundant gaseous PAHs compunds while phenanthrene, anthracene and pyrene were the highest ones in summer season. Fort he particulate phase PAH compounds phenanthrene and fluorene were found as the most abundant compunds while benzo[k]fluoranthene and benzo[a]pyrene compounds were the highest in summer season. The contribution of OC, EC and PAHs to road dust were determined as 11.4 ± 0.26 %; 1.91 ± 0.31 %; 0.25 ± 0.12 %, respectively. Benzo[k]fluoranthene, pyrene, benz[a]anthracene and fluoranthene were found to have the highest concentration PAHs. PAH concentrations determined from tunnel road dust were higher than the literature values.