PAHs also known as polycyclic or polynuclear aromatic hydrocarbons are organic compounds containing only carbon and hydrogen in the arrangement of a fused ring structure containing at least two benzene rings. They are produced during the incomplete combustion of wood and fossil fuels like coal, charcoal, gasoline and diesel fuel. Some are used in the manufacturing of dyes, insecticides and solvents. The higher molecular weight PAHs like benzo(a)pyrene are produced during combustion, while lower molecular weight compounds like naphthalene are obtained from crude oil.