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Volatile Organic Compound (VOC)

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Volatile Organic Compounds (VOCs) are organic chemical compounds that have high enough vapor pressures under normal conditions to significantly vaporize and enter the atmosphere. VOCs are sometimes accidentally released into the environment, where they can damage soil and groundwater.

The United States Environmental Protection Agency (EPA) defines a VOC as any organic compound that participates in a photoreaction; others believe this definition is very broad and vague as organics that are not volatile in the sense that they vaporize under normal conditions can be considered volatile by this EPA definition. The term may refer both to well characterized organic compounds and to mixtures of variable composition.

Contents

[edit] VOC by products

[edit] Emission Sources

  • Paints
  • Varnishes
  • Moth balls
  • Solvents
  • Gasoline
  • Newspaper
  • Cooking
  • Cleaning Chemicals
  • Vinyl floors
  • Carpets
  • Photocopying
  • Upholstery Fabrics
  • Adhesives
  • Sealing Caulks
  • Cosmetics
  • Air Fresheners
  • Fuel Oil
  • Vehicle Exhaust
  • Pressed wood furniture
  • Environmental Tobacco Smoke (Secondhand smoke)


[edit] Environmental effects

VOCs are sometimes accidentally released into the environment, where they can damage soil and groundwater. Vapours of VOCs escaping into the air contribute to air pollution.

VOCs are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane ((CH4) and non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere, although the effect varies depending on local air quality. Within the NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead to leukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses.

Some VOCs also react with nitrogen oxides in the air in the presence of sunlight to form ozone. Although ozone is beneficial in the upper atmosphere because it absorbs UV thus protecting humans, plants, and animals from exposure to dangerous solar radiation, it poses a health threat in the lower atmosphere by causing respiratory problems. In addition high concentrations of low level ozone can damage crops and buildings.


[edit] Health Effects

Acute

  • Nausea / Vomiting
  • Dizziness
  • Asthma exacerbation
  • Eye, Nose, and Throat irritation
  • Headaches

Chronic

  • Cancer
  • Liver and Kidney damage
  • Central Nervous System damage

[edit] Contribution to indoor air pollution

Many VOCs found around the house, such as paint strippers and wood preservatives, contribute to sick building syndrome because of their high vapour pressure. VOC's are often used in paint, carpet backing, plastics, and cosmetics. The United States Environmental Protection Agency (EPA) has found concentrations of VOCs in indoor air to be 2 to 5 times greater than in outdoor air. During certain activities indoor levels of VOCs may reach 1,000 times that of the outside air. Not all organic compounds are volatile; many plastics (polymers) and other large molecules may not have significant vapor pressure at normal temperatures.

Air quality with reference to Volatile Organic Compound Emission.


[edit] External links


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