Some of the most polluted air you can breathe isn't downtown but inside your own home. Surprised? Studies from the Environmental Protection Agency show typical airborne pollutants now run two to five times higher indoors than out, especially now that auto emissions and industrial smoke have been curbed.
Blame it on household chemicals and appliance vapors, along with molds accumulating inside tightly sealed houses. Americans already spend 90 percent of their time indoors, the EPA says, and approaching winter weather augurs months of more confinement. But with maintenance and savvy consumer choices, you can clear the air.Toxic offices previously took this rap. Remember sick building syndrome? Hermetically sealed high-rises with dirty air-conditioning systems or noxious building materials, can sicken employees. Now, the home is drawing attention as a zone of concentrated chemical vapors, fuels, appliance byproducts and biological detritus from pets or pests.
Hazards vary from house to house, but high levels of chemicals can exacerbate respiratory illness like asthma, and increase the risk of cancer or other chronic disease.
Combustion byproducts from heaters and stoves, for example, include particulates and nitrogen oxides. Poorly vented fireplaces or kerosene heaters give off carcinogens known as PAHs (polycyclic aromatic hydrocarbons). Gas stoves emit nitrogen oxides that inflame the lungs and trigger asthma. Malfunctioning heaters can leak deadly carbon monoxide, as do cars or lawnmowers running inside an attached garage.
Schedule annual maintenance checks, and make sure gases are vented outdoors. Wood-burning stoves should have proper vents, and can be equipped with catalytic converters. Households with asthma sufferers might even consider switching from a gas to an electric range.
Secondhand cigarette smoke "puts you in a league of your own" for high levels of nitrogen oxides, particulates and volatile organic compounds such as benzene and toluene, says Tim Buckley, assistant professor at the Johns Hopkins School of Public Health.
Highly allergenic mold and mildew spores, visible as a black residue on walls and windows, are a souvenir of last winter's El Nino storms and floods. Humidity also nurtures bacteria that emit airborne toxins, says George Malindzak, medical physiologist at the National Institute of Environmental Health Sciences, Research Triangle Park, N.C.
Mold and bacterial toxins cause lung disease when airborne. Bleach kills both, and dehumidifiers can dry up the moisture they need to grow.
Dust mites also thrive in high humidity, inflaming lungs of asthma sufferers. Federal studies in progress are asking whether intensive cleaning and pest abatement can stem the rising tide of childhood asthma, says Dr. Malindzak.
Formaldehyde, a staple ingredient in paints and plywood, is an animal carcinogen and possible human carcinogen, says Elissa Feldman, associate director of the EPA's Indoor Environments Division. Using such products calls for extra ventilation. If possible, consider alternative furniture materials. If you must use compressed wood, she advises sealing raw wood edges, and choosing "exterior-grade plywood," which releases less chemical gas than the interior grade.
Limit your exposure to mothballs and long-acting deodorizers containing paradicholorbenzene, an animal carcinogen with unknown long-term human effects. EPA advises sealing them in trunks and storing in a detached garage or ventilated attic. A benign alternative: cedar chips.
Wall-to-wall carpet can be a hot zone of both chemical and natural toxins. Carpet adhesives and backing can contain chemicals such as styrene, a suspected carcinogen, and 4-PC, the source of pungent "new-carpet" odor. The effects of long-term exposure are unknown. But the Carpet and Rug Institute, an industry group, conducts voluntary testing and labeling of carpets for chemical emissions. Look for the CRI label as a "minimal standard," advises Environmental Building News, an ecologically minded newsletter.
Consider Wood Floors and area rugs that can be removed and cleaned. If you're installing carpet, ask workers to unroll and air it out before laying it down. Old carpet, a reservoir for dust, pet dander and mold, should be replaced.
Dry cleaning uses the solvent perchloroethylene, an animal carcinogen that can linger inside plastic bags. Air out freshly dry cleaned clothes before bringing them into the house. Reject items with overpowering chemical smell, and ask your cleaner to extract the chemical and dry clothing properly. Safer fabric-cleaning technologies now under development include liquid carbon dioxide and water-based processes, says EPA pollution expert Blair Martin.
Avoid releasing clouds of aerosols, cleaners, solvents, paint strippers and hobby chemicals when your house is shuttered for the winter. Choose trigger sprays over aerosols.
Try to occasionally open windows and doors to invite a gust of fresh air. "How much can be ameliorated by opening windows? Quite a bit," says Bill Pease, a toxicologist with the Environmental Defense Fund in Oakland, Calif. Debate rages over value of air cleaners. They can purge airborne irritants but leave behind chemicals and allergens imbedded in drapes or carpets. Remember to clean filters; dirty ones can compound the problem.