| บทคัดย่อ(English) |
This study aims to investigate horizontal distribution of particle-bound polycyclic aromatichydrocarbons (pPAHs) at different configuration of road, Sukumvit Road (Road covered with BTSsky train structure), Rama VI Road (road covered with expressway), and Payathai road (openstreet). The study on distribution along the road, perpendicular direction to the road, anddistribution at different road configuration at the same period were performed. The study wasdesigned to compare between wet season (SeptemberNovember 2004), and dry season (March - April2005). The concentrations of total pPAHs were measured by Photoelectric Aerosol Sensor(PAS2000CE). The results show that the average pPAHs concentrations distributed along the roadat Sukumvit Road, including Prakanong BTS station, Srivikorn School, and Ekamai intersectionwere 389.5 , 217, and 286.5 ng/m('3), respectively, and those at Rama VI Road, including TISI,Samsanevitayalai School, and Tuk Chai intersection were 248, 115, and 327.5 ng/m('3),respectively. The significant difference of pPAHs distributed along the road might be caused bydifferent road configuration. Distribution of pPAHs along perpendicular direction to the roadat the distances less than 5, 75, 150, and 225 meters at Sukumvit Road, Rama VI Road andPayathai Road was investigated. In the cases of the wind blowing from the road towards thesampling and the wind blowing parallel to the road, the pPAHs measured at the distances farfrom the road (i.e. 75, 150, and 225 m.) decreased by the factors of 0.35, 0.22, and 0.2,respectively. While in the wind blowing towards the road, the factors were 0.65, 0.45, and 0.4,respectively. Local wind speed and wind direction were predominant factors affectingperpendiculary distribution. For distribution of pPAHs at three different road configurations,i.e. TISI, Prakanong BTS station, and Chulalongkorn University, the significant differentvalues of 254.5 , 339, and 93 ng/m('3) respectively, were obtained. The multiple regressionmodel for predicting hourly average pPAHs concentrations at different road configurations hasbeen performed. Volume of bus and truck, and of pickup and van, and wind speed were importantfactors for prediction of pPAHs distribution. In addition, relationship between total PAHsconcentrations and concentrations of particulate matters (PM(,2.5) and PM(,10-2.5)) wasexamined. A good linear correlation could be obtained with the R('2) values of 0.778 and 0.761,respectively. Predominant PAHs species adsorbed on PM(,2.5) were BkF, BaP, Ind, DBahA, andBghiP, while Phe, Anth, Fluor, BbF, and DBahA were mainly found in PM(,10-2.5). |
