10 Indoor Pollutants

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.