Green
Indoor Air Quality
The issue of indoor air quality (IAQ) gained attention in the 1980swith the identification of sick building syndrome. Sick building syndrome (SBS) is a combination of ailments associated with an individual's place of work or residence. The causes of SBS are frequently tied to flaws in the heating, ventilation, and air conditioning (HVAC) systems, but are also attributed to contaminants produced by out-gassing of VOCs from some types of building materials.
Volatile organic compounds (VOCs) are chemical compounds that under normal conditions vaporize and enter the atmosphere. One of the main VOCs implicated in SBS is formaldehyde. Formaldehyde is an important chemical used widely by industry to manufacture certain building materials, as well as numerous household product). Building materials that contain high levels of added formaldehyde are of concern because they can "off-gas" formaldehyde into building interiors and affect interior air quality long after the products are installed.
Formaldehyde, a colorless, pungent-smelling gas, can cause watery eyes, burning sensations in the eyes and throat, nausea, fatigue, and difficulty in breathing in some humans exposed at elevated levels (above 0.1 parts per million). Some people are very sensitive to formaldehyde, while others have no reaction to the same level of exposure. High concentrations may trigger attacks in people with asthma. It has also been shown to cause cancer in animals and is believed to cause cancer in humans.
The US Environmental Protection Agency (EPA) has classified formaldehyde as a probable human carcinogen (cancer-causer) under conditions of unusually high or prolonged exposure. The International Agency for Research on Cancer (IARC), however, upgraded its initial classification of formaldehyde as a probable human carcinogen to a known human carcinogen in 2004. The California Air Resources Board (CARB) supported the IARC findings by classifying formaldehyde as a "toxic air contaminant" after state experts concluded that, based on current research, there is "no safe exposure threshold [for formaldehyde] to preclude cancer."
In residential and commercial construction, the most significant sources of formaldehyde are likely to be pressed wood products made using adhesives that contain urea-formaldehyde (UF) resins. Engineered wood flooring, which is basically multiple layers of wood glued together to form a single piece, is one example of a pressed wood product whose adhesives more often than not contain urea-formaldehyde. Other pressed wood products made for indoor use include particleboard, hardwood plywood, and medium density fiberboard (MDF). MDF contains a higher resin-to-wood ratio than any other UF pressed wood product and is generally recognized as being the highest formaldehyde-emitting pressed wood product.
Other pressed wood products, such as softwood plywood and oriented strandboard, are produced for exterior construction use and contain the dark, or red/black-colored phenol-formaldehyde (PF) resin. Although formaldehyde is present in both types of resins, pressed woods that contain PF resin generally emit formaldehyde at considerably lower rates than those containing UF resin.
IAQ Limits for Formaldehyde
| Organization | Limit for formaldehyde emissions in parts-per-million (ppm) |
| Occupational Safety and Health Administration's (OSHA) | Below 0.75 ppm |
| U.S. ANSI | Below 0.30 ppm |
| European E1 standard | Below 0.10 ppm |
| Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard | Hazard warning labels on any manufactured product that may emit 0.10 ppm or greater |
| State of California (CARB limits) | Below 0.05 ppm |