Volatile organic compounds (VOC) are organic compounds that are emitted as gases from a variety of liquids and solids during use or storage. They are described as "volatile" because they evaporate easily, releasing molecules of often toxic substances into the air.
Volatile organic compounds are produced naturally, in usually tiny amounts, by animals, plants and microorganisms. However, they are also produced industrially in huge quantities and used as ingredients in an extensive variety household and industrial products and processes, including gasoline and other fuels, solvents for surface cleaning, dry cleaning chemicals, aerosol sprays, paint strippers, wood preservatives, and paints, varnishes and other coatings.
The most common volatile organic compound to which many people are exposed is formaldehyde because it is used in such a broad range of household products, including furniture and other pressed wood products, flooring, carpets, molded plastics and lacquers. Among the many others frequently encountered are benzene, ethylene glycol, methylene chloride, tetrachloroethylene, toluene, xylene and 1,3-butadiene.
Volatile organic compounds can have short-term or long-term effects on the health of humans and other organisms, including causing respiratory damage, damaging the central nervous system, and even causing cancer. They themselves can be directly an air pollutant, but they can also play a role in forming other air pollutants, such as the formation of ozone and thus smog when they are exposed to sunlight and heat along with sulfur dioxide and nitrogen oxides.