Polycyclic aromatic hydrocarbons (PAHs), or polyarenes, are one of the largest and most structurally diverse class of organic molecules known. High percentages of polyarenes, representing a wide range of molecular sizes and structural types, are present in coal tars and petroleum residues. The major sources of PAHs are crude oil, coal and oil shale. The fuels produced from these fossil sources constitute the primary source of energy for the industrial nations of the world, and the petrochemicals...
