Volatile Organic Compounds Volatile Organic Compounds or VOCs are organic chemicals that easily vaporize at room temperature. They are called organic because they contain the element carbon in their molecular structures. VOCs have no colour, smell, or taste. Hydrocarbon VOCs are usually grouped into methane and other non-methane VOCs. Methane is an important component of VOCs, its environmental impact principally related to its contribution to global warming and to the production of ground level or lower atmosphere ozone .
Most methane is released to the atmosphere via the leakage of natural gas from distribution systems.
Benzene, a non-methane hydrocarbon, is a colourless, clear liquid. It is fairly stable but highly volatile, readily evaporating at room temperature. Benzene concentrations are highest along urban roadsides. Oxygenates arise in vehicle exhausts and via atmospheric chemical reactions. Evaporation of solvents, used for example in paints, cause a release of hydrocarbons, oxygenates and halocarbons to the atmosphere.