Indoor air has become a huge issue in green building because it hits so close to home. Studies have shown indoor air can be even more dangerous than outdoor air, says the Environmental Protection Agency.

INSIDE JOB: Residential green building programs encourage products that keep contaminants out of a home. Clockwise from left: Liquid Nails offers a Greenguard-certified drywall adhesive; Panasonic has Energy Star-rated bathroom fans; and the Timber Products Co. just got its entire product line certified by the California Air Resources Board as low in formaldehyde emissions.

INSIDE JOB: Residential green building programs encourage products that keep contaminants out of a home. Clockwise from left: Liquid Nails offers a Greenguard-certified drywall adhesive; Panasonic has Energy Star-rated bathroom fans; and the Timber Products Co. just got its entire product line certified by the California Air Resources Board as low in formaldehyde emissions.

Homeowners aren't the only ones concerned about this. A 2007 survey of builders by ProSales' parent company, Hanley Wood, found that indoor air quality came second on the list of five green qualities that matter most.

The building world is speckled with stories of professionals who turned green because of indoor air concerns. GreenDepot, a green building material dealership based in New York, launched partly because its creator had concerns over the air quality issues affecting her child. And saving Mother Earth wasn't the sole motive of Yolo Colorhouse founders when they decided to create their paint product. "My partner and I were painters, and we started feeling the effects that working with conventional latex paints had on our health," says Janie Lowe, co-founder of Yolo Colorhouse.

The Programs. Three major residential green building programs–NAHB's National Green Building Program, LEED for Homes, and Energy Star's Qualified New Homes program–have sections in their rules regarding indoor air quality. Dealers can help builders by providing products that emit a lower amount of harmful substances than mainstream offerings, or products that help prevent contaminants from entering or building up inside a home.

NAHB's program has a section, called Indoor Environmental Quality. Of the 222 minimum points required for certification, 36 must come from the indoor air section. Of the six sections in the program, indoor air quality ranks third in points required.

Builders who erect an Energy Star home can choose to have a label, called the Indoor Air Package, added to the house.

LEED for Homes, run by the U.S. Green Building Council, also has an Indoor Environmental Quality section. Builders can choose to complete Energy Star's Indoor Air Package to earn points, or they can follow steps LEED provides. Of the 45 minimum points that it requires for certification, 13 must come from the indoor air section. That is the highest amount of required points for any of LEED's sections. Some measures for better indoor air are also listed under the Materials and Resources section.

Wood Products. The programs have provisions that address formaldehyde emissions in wood products. According to the EPA, the most significant sources of formaldehyde are likely to be pressed wood products. Formaldehyde can cause burning sensations in the eyes and throat, nausea, and difficulty in breathing. It may even cause cancer among people exposed to elevated levels above 0.1 parts per million (ppm). In homes with "significant amounts of new pressed wood products," the agency states, "levels can be greater than 0.3 ppm."

Energy Star requires that particleboard and MDF be certified as compliant with specific lower formaldehyde emissions requirements: ANSI A208.1 and ANSI A208.2, respectively. NAHB awards points for this.

Energy Star requires hardwood plywood products to comply with other low emissions standards: ANSI/HPVA HP-1-2004 and U.S. HUD Title 24, Part 3280. NAHB also awards points for these measures.

In addition, NAHB gives points for composite wood or agrifiber panel products that have no added urea-formaldehyde or meet requirements from the California Air Resources Board. Non-emitting wood products also can receive points.

LEED, along with NAHB, awards points for hard flooring products that are FloorScore certified by the Scientific Certification Systems to have lower harmful emissions than mainstream products. NAHB also accepts hard-surface manufactured flooring as certified by the Greenguard Children & Schools Product Certification Program.

SCORE KEEPER: Temple-Inland's UltraStock-Free MDF is manufactured with a resin that contains no urea-formaldehyde, so it qualifies for points under green building programs.

SCORE KEEPER: Temple-Inland's UltraStock-Free MDF is manufactured with a resin that contains no urea-formaldehyde, so it qualifies for points under green building programs.

Low-Emissions Products. Wood products aren't the only materials that can emit harmful substances. Both NAHB and LEED award points for the use of coatings, sealants, and adhesives with low amounts of volatile organic compounds (VOCs). VOCs are a probable source of short- and long-term negative health effects, such as headaches and dizziness, the EPA says.

EPA studies found that levels of about a dozen common organic pollutants were two to five times higher inside homes than outside, whether the homes were in rural or highly industrial areas. Michelle Moore, senior vice president of policy and public affairs for LEED for Homes, says using low-VOC products is one of the easiest ways builders can earn LEED points.

Attached Garages. Attached garages mean huge sources of harmful emissions, such as from cars and trucks, are right next to a home.

Energy Star requires common walls and ceilings between an attached garage and living space to be air-sealed before installing insulation. LEED awards points for builders that minimize pollutants from the garage by sealing all penetrations, weather-stripping all doors, and sealing all cracks at the base of walls for conditioned spaces next to the garage. NAHB's program gives builders points for tightly sealing doors and having a continuous air barrier between walls and ceilings in attached garages.

Ventilation. As most building professionals know, ventilation is crucial to keeping a home healthy. Not enough ventilation can mean indoor pollutants, such as emissions from cleaning products, build up in a home. High humidity, such as in bathrooms, can cause mold and mildew.

LEED for Homes and Energy Star require whole-house ventilation that meets ASHRAE 62.2 standards. ASHRAE voluntary standards are designed to go beyond required codes to promote healthy indoor environments. The NAHB's program awards points for whole-house ventilation that meets ASHRAE 62.2 Section 4, but does not require it.

LEED and Energy Star also require that Energy Star-labeled exhaust fans are used in bathrooms, except for a fan serving multiple bathrooms. The NAHB program awards points for Energy Star fans.

While none of these measures completely ensures a home will be free of indoor air problems, it gives homeowners more than a good start to keeping safe home environments. Dealers are a great resource for products that help keep indoor air safe, as well as products that are safer for indoor air than mainstream offerings.

–Victoria Markovitz