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Volatile organic compounds (VOCs) are organic chemicals that have a high vapor pressure at ordinary room temperature. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and enter the surrounding air. For example, formaldehyde, which evaporates from paint, has a boiling point of only –19 °C (–2 °F). VOCs are numerous, varied, and ubiquitous. They include both human-made and naturally occurring chemical compounds. Most scents or odors are of VOCs. VOCs play an important role in communication between plants, and messages from plants to animals. Some VOCs are dangerous to human health or cause harm to the environment. Anthropogenic VOCs are regulated by law, especially indoors, where concentrations are the highest. Harmful VOCs typically are not acutely toxic, but have compounding long-term health effects. Because the concentrations are usually low and the symptoms slow to develop, research into VOCs and their effects is difficult. == Definitions == Diverse definitions of the term VOC are in use. The definitions of VOCs used for control of precursors of photochemical smog used by the EPA and states in the US with independent outdoor air pollution regulations include exemptions for VOCs that are determined to be non-reactive, or of low-reactivity in the smog formation process. EPA formerly defined these compounds as reactive organic gases (ROG) but changed the terminology to VOC. In the USA, different regulations vary between states - most prominent is the VOC regulation by SCAQMD and by the California Air Resources Board.〔(California ARB )〕 However, this specific use of the term VOCs can be misleading, especially when applied to indoor air quality because many chemicals that are not regulated as outdoor air pollution can still be important for indoor air pollution. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Volatile organic compound」の詳細全文を読む スポンサード リンク
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