The researchers analyzed 11 types of petroleum fuels and lubricants to study their polycyclic aromatic hydrocarbons (PAHs) content. They found that naphthalene was the main compound in gasolines, jet fuel, and kerosene, while bunker A and bunker C had higher levels of dibenzothiophene and other heavy PAHs. Different refining temperatures and boiling points of PAHs led to variations in PAH compositions among the fuels. By analyzing the ratios of specific alkyl homologs, the researchers were able to classify the oil samples into five groups: gasolines, light oil, bunker oils, kerosene, and quench oil. This detailed profile of PAHs in petroleum fuels can be used to identify the source of oil spill accidents in the environment.