The higher the volatility (lower the boiling point), the more likely the compound will be emitted from a product or surface into the air. Semi-volatile organic compounds (SVOCs).Very volatile organic compounds (VVOCs).For example, the World Health Organization (WHO) categorizes indoor organic pollutants as: VOCs are sometimes categorized by the ease they will be emitted. Since the volatility 4 of a compound is generally higher the lower its boiling point temperature, the volatility of organic compounds are sometimes defined and classified by their boiling points.įor example, the European Union uses the boiling point, rather than its volatility in its definition of VOCs.Ī VOC is any organic compound having an initial boiling point less than or equal to 250° C measured at a standard atmospheric pressure of 101.3 kPa. This is the general definition of VOCs that is used in the scientific literature, and is consistent with the definition used for indoor air quality. 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 3. Volatile organic compounds (VOC) means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates and ammonium carbonate, which participates in atmospheric photochemical reactions, except those designated by EPA as having negligible photochemical reactivity 2. In addition, the measured quantity and composition of VOCs in the air can vary significantly depending on the measurement methods used, which has generated additional confusion. This has created a misunderstanding in the marketplace and in the environmental community.
While VOCs can also be a health concern outdoors, EPA regulates VOCs outdoors mainly because of their ability to create photochemical smog under certain conditions.Īlthough the same term “VOC” is used for both indoor and outdoor air quality, the term is defined differently to reflect its predominant concern in each context. The main concern indoors is the potential for VOCs to adversely impact the health of people that are exposed. However, the emphasis of that concern outdoors is different from indoors. VOCs are of concern as both indoor air pollutants and as outdoor air pollutants. Indoors, VOCs are mostly released into the air from the use of products and materials containing VOCs.Outdoors, VOCs are volatized or released into the air mostly during manufacture or use of everyday products and materials.Organic chemical compounds 1 are everywhere in both indoor and outdoor environments because they have become essential ingredients in many products and materials.