A naturally occurring volatile organic compound, it is a component of petroleum and coal and is released by the burning of wood or tobacco. It is also used in moth repellants, dyes and pharmaceuticals. Like other nonmethane hydrocarbons it is oxidized and subsequently it reacts with NO in the atmosphere to produce NO₂. The NO₂ is photolyzed to produce NO and O. The O then reacts with O₂ to produce ozone.