什麼是VOC?

Volatile organic compounds (VOCs) are organic chemical compounds that have high enough vapour pressures under normal conditions to significantly vaporize and enter the atmosphere. (The term VOC is also occasionally used as an abbreviation, especially in biological contexts, for "volatile organic carbon".) A wide range of carbon-based molecules, such as aldehydes, ketones, and hydrocarbons are VOC's. The term often is used in a legal or regulatory context and in such cases the precise definition is a matter of law. These definitions can be contradictory and may contain "loopholes"; e.g. exceptions, exemptions, and exclusions. Others believe the concept that a volatile organic compound is any organic that participates in a photoreaction, as found in the EPA's definition, is very broad and vague. Organics that are not volatile, as described above, can fall into that definition. The term may refer both to well characterized organic compounds and to mixtures of variable composition. Most often the definition used is one from the United States Environmental Protection Agency (see below).

Contents [hide]
1 Sources of VOCs
2 Environmental Effects
3 Contribution to Indoor Air Pollution
4 Terminology and legal definitions
4.1 US EPA CFR Definition
4.2 European Union Definition
4.3 Classification in the UK
5 Other relevance
6 See also
7 External links



[edit] Sources of VOCs
Common artificial sources of VOCs include paint thinners, dry cleaning solvents, and some constituents of petroleum fuels (eg. gasoline and natural gas). Trees are also an important biological source of VOC. It is also known that trees emit large amounts of VOCs especially isoprene and terpenes. Significant biological sources of methane are termites, cows (ruminants) and cultivation (estimated emissions 15, 75 and 100 million tons per year respectively).

Another significant source of VOC emission is crude oil tanking. Both during offloading and loading of crude oil tankers VOC are released to the atmosphere. Lately there has been an environmental focus on this issue resulting in both VOC handling on newer tankers and also crude oil loading terminals.

揮發性有機物 (VOCs - Volatile Organic Compounds)

多類有機物質
例如︰苯、三氯甲烷及二甲苯
在室溫中揮發
部份在室內找到的有機物乃廣為人知的致癌物質，例如︰苯和甲醛
來源︰

溶劑、清潔劑、木料、油漆、塑膠、染料、辦公室文儀器材 (傳真機、電腦、打印機等）及殺蟲劑等
影響︰

令眼鼻喉及呼吸道受到刺激、頭痛、精神不習中、暈眩及疲倦
損壞中央神經系統、肝臟及腎臟
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一些家居用品如個人電腦等可釋放揮發性有機物。
清潔劑是室內揮發性有機物的來源之一。