Volatile organic compounds, or VOCs, are common indoor air pollutants. Being volatile, they evaporate easily, and being organic, they contain carbon.
VOCs can originate from a variety of natural sources. The characteristic odor of mold is composed of VOCs, as is the smell of an orange or an onion. Baking bread also releases VOCs into the air. Indoor air typically contains 30-100 different VOCs that are readily measurable, and others at low levels that are more difficult to measure. Some VOCs cause no health problems, but others are serious indoor air pollutants.
VOCs are also given off, or outgassed, from many manufactured products. Familiar sounding VOCs might include benzene, xylene, toluene, formaldehyde, and ethanol. These can all be released from typical building materials.
One study determined that the following were the most common VOCs found in indoor air: benzene, toluene. exlenes, styrene, ethylbenzene, ethyl methly benzenes, trimethyl benzenes, dimethyl-ethylbenzenes, naphthalenes, propyl-methylbenzenes, n-propyl benzene, diethyl benzenes, tetrachloroethylene, 1,1,-trichloroethane, trichloroethylene, dichlorobenzenes, trichlorofluoromethane, dichloromethane, chloroform, ethyl acetate, m-hexyl butanoate, 2-ethyl-1-hexanol, n-hexanol, 2-butyloctanol, n-dodecanol, n-nonanal, n-devanal, acetone, acetic acid, dimethylphenols, ethylene oxide, undecane, 2-methylhexane, 2-methylpentane, 3-methylhexane, 3-methylpentane, octane, decane, dodecane, tridecane, methylcyclohexane, heptane, tetradecane, 2-methylheptane, cyclohexane, pentadecane, hexane, eicosane, 3-methylnonane, and 1,3-dimethyl-cyclopentane.
Because there are so many different VOCs found indoors, and because so few of them have been studied thoroughly, it’s often easier for scientists to talk about the TVOC or total VOC concentration. This can be useful for cataloging, but it does nothing to identify the health effects attributable to specific compounds. One source has suggested that 200 micro grams per cubic meter (µg/m3) is a level that has no effect on most people, however some sensitive people could react to that level. Outdoor TVOC levels are generally about 100 µg/m3, and one Canadian study found that indoor levels ranged from 100 to 100,000 µg/m3, although most homes registered in the 1,000-3,000 µg/m3 range.
(Note: This article is part of the original HHI Archives, and was believed to be accurate at the time of writing. The views expressed in this article are those of the author, and do not necessarily represent those of The Healthy House Institute, LLC.)
