Volatile Organic Compounds
Volatile organic compounds (VOCs) are carbon-containing gases and vapors such as gasoline fumes and solvents (excluding carbon dioxide, carbon monoxide, methane, and chlorofluorocarbons). Many individual VOCs are known or suspected of having direct toxic effects on humans, ranging from carcinogenesis to neurotoxicity. The more reactive VOCs combine with nitrogen oxides (NOx) in photochemical reactions in the atmosphere to form ground-level ozone, a major component of smog.