Polycyclic Aromatic Hydrocarbons (PAHs). Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that occur naturally in coal, crude oil, and gasoline. They also are produced when coal, oil, gas, wood, garbage, and tobacco are burned.PAHs generated from these sources can bind to or form small particles in the air.High-temperature cooking will form PAHs in meat and in other foods.hey also are produced when coal, oil, gas, wood, garbage, and tobacco are burned. PAHs generated from these sources can bind to or form small particles in the air. High-temperature cooking will form PAHs in meat and in other foods.