10 Indoor Pollutants

These are the most common household threats to the air quality in your home.

Indoor Pollutants

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We spend a large part of our lives indoors yet the idea of indoor air pollution can be easy to dismiss, especially if no one in our home has health problems. The unfortunate catch is that while the effects of many indoor air pollutants can show up soon after exposure, they can also show up years later as cancers, reproductive health problems, and more.

1. Volatile organic compounds. VOCs are chemical compounds that can off-gas, or evaporate easily, in normal temperatures and pressures. Health effects vary from headaches and dizziness to increased cancer risk, depending on the individual and combination of VOCs and the level and length of exposure. We introduce VOCs into our homes through our choices in paints, cleansers, hobby supplies, furniture, cabinetry, stored fuels, dry cleaning, and more.

Anthony Bernheim, indoor air quality expert and principal of Sustainable Design Solutions for HDR Architecture, Inc. in San Francisco, CA, says that air testing in an office building found that chemicals from dry cleaning were in the indoor air and being transmitted to the building from dry-cleaned clothing brought from employees’ homes.

To reduce risks, buy low- or no-VOC products. If you do choose products with VOC emissions, read product labels and obey cautions. Dispose of old or unneeded containers during special community toxic waste collection drives or check with your local government about disposal. Bernheim suggests finding an environmental dry cleaner. As an alternative, remove dry cleaning from its plastic bag; bring it home in the car trunk, and air out clothes for a few days in a well-ventilated area before bringing them inside.

2. Ozone. “Climate change is bringing increased sunlight and warmer temperatures to some areas,” says Bernheim. “Those hot sunny days trigger the formation of ground-level ozone, an odorless gas which can cause respiratory problems.” But there is an added catch: “Open your window and the ozone moves inside. There it causes secondary reactions with emissions from household sources that are different from—and, at times—more harmful than initial concerns.”

To lessen impacts, be aware of local ozone levels if you plan to use certain products. Check the Air Quality Index that calculates levels of ozone and four other major pollutants across the country. Reduce or eliminate VOC sources in your home that may react with ozone.

3. Occupation and location pollutants. Where we work can affect the air in our homes. “Auto body repair, paint shops, industrial plants, manufacturing sites may all contain chemical pollutants that attach to the clothes that we wear,” Bernheim says. “We bring them home on our clothing, walk them into our carpets, and they then release into the indoor air.” Where we live also is a factor. “Those who live near freeways or on a street corner subject to traffic stopping and starting face the added pollutants of diesel, a greenhouse gas, as well as carbon dioxide, sulfur dioxide and ozone,” Bernheim says.

As a precaution, take a shower after work and/or remove work clothing and shoes before entering your home. Before opening windows, be aware of local air quality (check the Air Quality Index). If you live near a freeway, for instance, opening windows at 8 a.m. may bring in particulate matter, diesel fumes, and carbon emissions from the rush hour.

4. Radon. It may be tasteless, odorless, and invisible, but radon gas is the second leading cause of lung cancer in the U.S. Radon is produced when naturally occurring uranium decays in soil and water. The gas seeps into homes through foundation cracks or seams. While general radon zones help agencies better target resources, the EPA suggests that all homes be tested because elevated levels have been found in each zone.

Test kits that are state-certified or meet the requirements of a national radon proficiency program can be expensive. Homeowners may also decide to hire a trained, qualified contractor to conduct the testing. It’s typically best to test during the heating season because ventilating the house by opening windows and doors frequently can skew the results. A short-term test takes at least two days and can last up to six days. If test results come back with a high radon level, a second short-term test can be taken and the results averaged. A long-term test of more than 90 days may provide more typical results for year-round exposure. Before beginning a test, keep the house closed for at least 12 hours.

5. Lead. Although the Product Safety Commission issued a ban in 1977, the EPA suggests there are millions of homes that still contain some lead-based paint. Adverse effects are now known to occur at much lower levels of lead in blood than previously thought. Many homeowners may unknowingly expose their household to lead dust when paint is scraped, sanded, or stripped or painted areas are demolished. Even without renovations, lead-based paint can deteriorate, releasing dust.

Starting in April 2010, the EPA’s Lead: Renovation, Repair and Painting Program rule mandated lead-safe work practices and certification and training for paid contractors and maintenance professionals working in pre-1978 housing, as well as child-care facilities and schools. For those planning DIY projects,  the Lead Paint Safety Field Guide is useful.

6. Asbestos. According to the Consumer Product Safety Commission, you can’t tell simply by looking at something where it contains this mineral fiber unless it’s labeled. Asbestos was once used in floor tiles, ceiling tiles, roof shingles, flashing, siding, insulation around ducts, pipes and fireplaces, and vermiculite attic insulation, among other places. “Asbestos becomes a major concern as people remodel, weatherize, rehab, or demolish old homes,” says Michael Vogel, Ed.D., Montana State University, head of the Healthy Indoor Air for America’s Home program.

The problem is that if disturbed, deteriorated, or damaged, asbestos materials may release fibers. Asbestos has a long-term impact that is related to the number of loose fibers inhaled. Those fibers end up raising the risks of chest and abdominal cancers and lung diseases. Before demolishing an area or working in an area with damaged or deteriorating materials that are in question, contact a qualified professional to test samples or to take control measures. If asbestos material is undamaged and unlikely to be disturbed, the CPSC suggests it be left alone.

7. Biological contaminants. Mold, bacteria, mildew, animal dander, cat saliva, mites, cockroaches, and pollen give us everything from allergic rhinitis and lethargy to asthma. Two key ingredients to these pollutants are moisture and nutrients.

Some guidelines for your household are the following: Keep indoor relative humidity at 30 to 50 percent to inhibit the growth of biologicals. Remove water-damaged materials. Repair leaking pipes. Eliminate any damp environments that allow molds, mildew, bacteria, or insects to flourish.

8. Carbon monoxide/particulates. Colorless, odorless carbon monoxide as well as fine particulates and other combustion pollutants come from many sources. Their effects can be flu-like symptoms, serious illness or death. “With the last several years of higher energy costs and problems with the economy, a lot of folks are trying to really tighten their homes,” says Vogel. “But many don’t do a whole-house assessment. They can tighten their homes beyond what combustion air is need for appliances. That brings on carbon monoxide and other problems because the house is not allowed to breathe.”

Be sure to vent woodstoves and gas stoves in your home. Properly install and maintain chimneys and flues. In the annual furnace inspection, make sure the heat exchanger is not cracked. Refrain from smoking in the home. Consider installing a carbon monoxide alarm, use a properly sized range hood if there is a gas stove and vent all clothes dryers to the outside so moisture and particulates also can be removed.

9. Formaldehyde. Pungent and colorless, this gas can prompt irritating to life-threatening immediate reactions or reactions after repeat exposures. It’s found in many building materials and products, from pressed-wood drawer fronts and bookshelves to furniture tops, subflooring, and cabinets.

Before purchasing a product, ask about the formaldehyde content. New products can release increased amounts of formaldehyde when indoor temperatures or humidity is high, so provide plenty of ventilation. Emissions usually drop as products age. Check for alternative, formaldehyde-free products such as those offered by Columbia Forest Products.

10. Pesticides. Pesticides may not be thought of as indoor air pollutants yet the liquids, sprays, powders, crystals and foggers used to kill insects, termites, rodents, fungi, or microbes in our homes are just that. Pesticides also may be tracked in from yards or drift in through open windows. Depending on a pesticide’s mix, health effects may range from minimal to eventual damage to the central nervous system and kidneys and increased cancer risk.

To reduce impacts, take the manufacturer’s directions seriously. Don’t store chemicals in your home. Consider non-chemical methods. Keep indoor spaces clean and dry to reduce the chances of problems. Make informed decisions about pesticide use by visiting the National Pesticide Information Center.