What are VOCs?
Volatile organic compounds (VOCs) are carbon containing chemicals that vaporize and can enter the body through normal breathing. VOCs can come from many sources. They are used as ingredients in paints, cleaning products, and adhesives. They are released by building materials such as carpet, linoleum, composite wood products, and insulation to name a few. Office equipment such as printers, copiers, and fax machines may also emit VOCs.
VOCs are chemicals that have high vapor pressures and fairly low boiling points and that tend to vaporize from the liquid or solid state under normal atmospheric conditions. Vapor pressure relates to the equilibrium of a substance between its solid or liquid state and its gas state, that is, the rate at which a liquid evaporates or a solid sublimates. If the vapor pressure is high, then the substance will move to the gas phase more quickly. Substances with high vapor pressure at room temperature are said to be volatile. VOCs also often have low boiling points (often below room temperature) that contribute to their vaporization. Examples of some common VOCs are formaldehyde, benzene, toluene, limonene, and hexane.
Removing VOCs from the Air
Using an activated carbon (a carbon or charcoal that is very porous and has a large surface area) filter is the most reliable way to remove VOCs from the air. VOCs attach to and accumulate on the activated carbon in the process known as adsorption. These filters become exhausted or "spent" and must be frequently replaced. Otherwise, the adsorbed VOCs may desorb, or leave the surface of the activated carbon and return to the air.
CDPH's Position on VOCs
Part of the mission of the Indoor Air Quality (IAQ) Section is the reduction of exposure to indoor, airborne chemicals. In 2008, CDPH published the first health based standard for testing building materials for chemical emissions (Section 01350). Along with other agencies, CDPH has written purchasing guidelines that include IAQ criteria that mandate low chemical emissions. The department supports the California Air Resources Board's (CARB) formaldehyde regulation, which limits formaldehyde emissions from composite wood products.