Volatile organic compound

Description

Volatile organic compounds, or VOCs, are organic chemical compounds whose composition makes it possible for them to evaporate under normal indoor atmospheric conditions of temperature and pressure. These hydrocarbon gases are a major class of pollutant. They can be generated by combustion engines, paints and printing inks, gasoline pumps, cleaning solvents, chemical or metallurgical processes. In a major city, solvent fumes can average 500 tons per day.

VOCs are sometimes categorized by the ease they will be emitted. For example, the World Health Organization (WHO) categorizes indoor organic pollutants as:

• Very volatile organic compounds (VVOCs): Propane butane, methyl chloride, etc.
• Volatile organic compounds (VOCs): Formaldehyde, d-Limonene, toluene, acetone, ethanol (ethyl alcohol) 2-propanol (isopropyl alcohol), hexanal
• Semi-volatile organic compounds (SVOCs): Pesticides (DDT, chlordane, plasticizers (phthalates), fire retardants (PCBs, PBB))

The higher the volatility (lower the boiling point), the more likely the compound will be emitted from a product or surface into the air. Very volatile organic compounds are so volatile that they are difficult to measure and are found almost entirely as gases in the air rather than in materials or on surfaces. The least volatile compounds found in air constitute a far smaller fraction of the total present indoors while the majority will be in solids or liquids that contain them or on surfaces including dust, furnishings and building materials.

Synonyms and Related Terms

VOC

Resources and Citations

• P.Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002.
• EPA: Volatile Organic Compounds
• World Health Organization, 1989. "Indoor air quality: organic pollutants." Report on a WHO Meeting, Berlin, 23-27 August 1987. EURO Reports and Studies 111. Copenhagen, World Health Organization Regional Office for Europe.