The objective of this study was to find major PAHs produced in ambient air from the automobile exhaust as a function of fuels (diesel, petrol, and biodiesel) and engine type qualitatively and quantitatively. The recovery range was found between 30% and 70%. The study was carried out on two, three, and four wheelers. Biodiesel samples tested in the study were synthesized indigenously from different starting raw materials and analyzed for PAHs concentration in the exhaust on a Honda genset (EBK 2000AC Model). Biodiesel samples were blended with diesel in different ratio (25:75, 35:65 and 45:55) to investigate the exhaust behavior. Biodiesel was blended with Diesel the concentration of almost all PAHs reduces in comparison to pure Diesel exhaust. B(a)A and B(a) P was the common PAH found in higher concentration in almost all fuels. FTIR results indicate esterification of vegetable oil and NMR results indicate a complete conversion of oils into biodiesel.