Dilution is the solution to pollution

IT may have the ring of a cliché -- "dilution is the solution to pollution" -- but the saying does outline a basic strategy for improving indoor air quality. Reduce the pollution coming into the home, then dilute impurities already present.

Outgassers such as formaldehyde and volatile organic compounds, or VOCs, often enter the home when it's built and decorated. Controlling their effects can be as simple as replacing carpeting with a bamboo floor sealed in beeswax or as complex as working with a professional to bring more outdoor air into the home. The process requires research: reading labels, asking questions, being prepared to pay a little extra. Elements to consider:

Framing: Plywood, fiberboard and medium-density fiberboard with little or no formaldehyde are available but may be more expensive. To maximize benefits, they should be installed with formaldehyde-free adhesives.

Cabinets, shelving: Particleboard, used extensively in kitchen cabinetry, can be substituted with solid wood modules or open metal shelving. The shelving pictured on Page F1 is PureBond plywood, part of Columbia Forest Products' line of formaldehyde-free composite woods.

Sealers and adhesives: That "environment-friendly" bamboo flooring may be a good idea, but what kind of adhesive or moisture barrier was used underneath? A manufacturer may negate its warranty if a particular glue is not used, one that may contain VOCs.

Paint: Look for low- or zero-VOC paint, but also research levels of ammonia, formaldehyde, benzene and toluene. Or try plaster or products such as American Clay, a non-emitting finish that comes in an array of colors.

Flooring: Presealed wood flooring generally outgasses less than flooring that you seal post-installation. Alternatives include ceramic tile or polished concrete. Expanko makes cork and cork veneer tiles that are formaldehyde-free and use non-emitting adhesives in installation. Look for the FloorScore seal from the Resilient Floor Covering Institute, indicating compliance with California VOC emissions regulations.

Carpeting: Carpeting and padding are often outgassers. They also may collect VOCs, dust and other irritants.

Area rugs: Look for the Green Label Plus certification from the Carpet and Rug Institute, a nonprofit trade group. But remember: Even a lovely old Persian carpet may have a synthetic backing and could have been treated with a bactericide or a fumigant. Assume nothing. Try a Tibetan, untreated cotton or wool rug with the expectation that you'll have to deal with stains.

Upholstery: Place new upholstery in the garage to outgas for a month before moving it inside, or look for fabrics that have been shown not to outgas. Crypton Green, for example, is line of upholstery that outgasses less than conventional fabrics and contains recycled content too.

HVAC: Two studies presented at the Greenbuild conference last week indicated that residents often receive less fresh air via windows than had been presumed. A good heating, ventilating and air-conditioning system, or HVAC, is key to bringing outside air into the house, flushing out chemicals and filtering impurities. One option is to put an exhaust fan on the roof and a fresh-air intake vent that plugs into the existing ventilation system. Good air is brought into each room, and bad air is vented out. For a 2,000-square-foot house with ducting to all rooms, the cost may run about $2,000 installed.

Forced air: A less costly option is a unit that delivers at least 10% fresh air to the central air handler of your existing ventilation system. Fresh air is forced into the house, and bad air is forced out through cracks around doors and other ventilation leaks. These units start around $200 uninstalled but are DIY-friendly.

Exhaust fans: Single-point exhaust fans in kitchens and bathrooms are less expensive (under $100) but also less effective for improving air quality. They may suck air in from the garage, the attic or the inside of walls.