Profile of PAHs in soot collected from exhaust of diesel driven vehicles in Iloilo


by: Pilar Mercedes A.Retiracion, Rica P. Cainglet, Feby E. Carmen


Air pollution is a global issue. Motor vehicle emissions is one of the primary contributors to this phenomenon. There have been significant national and international efforts to reduce the worldwide distribution of pollutants, including the implementation of the Clean Air Act and the Motor Vehicle Air Pollution Control Act. In Iloilo City, urban development gave way to the increase in the number of business establishments and the number of operating vehicles as well. In this study, analysis of polycyclic aromatic hydrocarbons (PAHs), a component of particulate matter, which is one of the major categories of pollutants, was done in soot collected from the exhaust of vehicles. Two types of diesel fuelled vehicles were considered: bus and jeepney. Samples were prepared for analysis using modified EPA-8270-C determination of semi volatile compounds. Extracts were subjected to gas chromatography-mass spectrometry analysis. Total ion chromatograms (TIC) of the 16 US Environmental Protection Agency PAHs were initially produced and these were further examined by generating the extracted ion chromatograms (EIC). Confirmed PAH peaks were integrated and plotted to the calibration curves of the prepared external standards to calculate the concentrations of the PAHs. Results showed that five PAHs were detected, in various concentrations. Jeepneys have higher levels of PAH compared to buses. The highest total PAH concentration is recorded for jeepney (1-7 years) at 21. 67 ppm, while the lowest is for bus (8-14 years) at 1.32 ppm. Although confirmed to be present, the toxicity level to humans of these PAHs in soot is low due to limited direct exposure.

Keywords: Polycyclic aromatic hydrocarbons, motor vehicle, diesel