Updated on September 5, 2024.
You may have heard about the health effects of air pollution, and therefore assume that the best place to avoid this hazard would be indoors. The fact is, indoor air—whether in homes or offices—may actually be more polluted than outdoor air. What’s more, the average home contains hundreds of potential sources of worrisome pollutants, from cleaning supplies to carpets.
So how concerned should you be?
Research suggests that you’d have to breathe in unusually high levels of household pollutants for a long time to suffer serious health effects. But if you’re sensitive to chemicals and allergens, even low levels can trigger irritating reactions.
To help you understand some of the most common indoor air pollutants, answer these five questions and read on for tips on how to improve indoor air quality and breathe easier at home.
Avoid formaldehyde
Question: Formaldehyde can be found in which of these products? (More than one answer may be correct.)
a. Cosmetics and nail polish
b. Glues and adhesives
c. Pressed-wood products (such as plywood, particle board, and medium-density fiberboard, or MDF)
d. Foam insulation materials
e. Wallpaper
f. Wrinkle-resistant drapes, linens, and other fabrics
g. All of the above
The answer: All of the above
While formaldehyde is considered a “known carcinogen” (or cancer-causing agent), experts say the effect of typical home levels on cancer risk is low. Still, it’s worth the effort to avoid products that contain it. They can cause irritation of the eyes and nose, raise your risk of asthma or allergies, and may even cause certain neurological problems.
What you can do about formaldehyde
- Buy solid-wood products and antique furniture rather than new furniture made from pressed-wood products. As much as possible, seek housewares made from glass or metal, such as stainless steel. (If you do buy pressed-wood furniture or paneling, be sure it conforms to low-emission standards.) Agency stamps that certify such products include APA PS1 and PS2, ANSI, HPVA, ECC, CPA, Greenguard, KCMA, Green Wise, MPI, and CRI.
- Skip treated fabrics whenever possible.
- Check personal-care product ingredients for formaldehyde, and remove any you find from your home.
- Modulate the temperature and humidity levels in the home with air conditioners and dehumidifiers, and make sure the home is well-ventilated.
- If you suspect formaldehyde levels are high, buy a test kit or have a professional testing company test the air. Signs you may have formaldehyde exposure in your home include irritated eyes, nose, and throat, as well as headaches and feeling dizzy and nauseated.
Be mindful of VOCs
Question: Which of the following household products are likely to contain volatile organic compounds (VOCs)?
a. Air fresheners
b. Tap water
c. Freshly dry-cleaned clothing
d. Paint
e. Furniture
f. None of the above
g. All of the above
The answer: All of the above
VOCs are chemicals that become gases at room temperature. Their levels vary from home to home and room to room. If you painted a room in the past year, if you bought new carpet or furniture, or if anyone smokes in your house, you've probably inhaled VOCs. They may also be released by heavily chlorinated tap water and from the perchloroethylene (PCE) in your just-dry-cleaned sweater. In fact, VOCs are two to 10 times higher indoors than outside.
At high levels, VOCs may cause you to feel dizzy, nauseated, tired, and uncoordinated. Your ears, nose, and throat may become irritated, and you may have a skin reaction. A 2022 review of studies published in the International Journal of Environmental Research and Public Health found that high levels of VOCs in the home may be linked to asthma. It also noted that VOCs are associated with childhood acute leukemia.
What you can do about VOCs
- Buy floor models of furniture and appliances that have had time to "off-gas." (Off-gassing happens when VOCs are released from products over time.) Buy solid-wood, glass, or metal products when possible.
- Let fresh air in from the outdoors rather than using chemical air fresheners. Weather permitting, open doors and windows, and use fans to bring outside air in.
- Keep temperature and humidity as low as you can while still feeling comfortable. Low temperatures and humidity can help decrease off-gassing.
- Plan indoor construction and painting when you can vacate the house for a while or when it's warm enough to open windows and doors.
- Buy low-VOC, air-friendly cleaning products. Visit the U.S. Environmental Protection Agency (EPA) website for information on Safer Choice options. Keep household cleaners tightly sealed when not in use.
- Use VOC-free or low-VOC paint when possible and store materials with high VOC levels (such as solvents or paints) in a garage or shed, not in the house.
- If your dry-cleaned clothes have a chemical odor, ask the cleaner to dry them properly. If it happens again, try a different dry cleaner, preferably one that doesn't use perchloroethylene. Take cleaned clothes from the plastic wrap and let outdoor air circulate around them for at least an hour.
- If your tap water has a strong chlorine smell, open a window or turn on the exhaust fan when taking a hot shower or bath. Chloroform is created as waste from chemical and paper manufacturing and sewage treatment plants and is a by-product of chlorinated water. When exposed to large amounts, it can affect the nervous system. According to the EPA, it is a probable human carcinogen.
- You might consider having your home tested if you have sensitivity symptoms. Just know that it can be very expensive. The best place to start is to reach out to your local health department for advice on next steps.
Understanding radon risk
Question: Where does radon come from?
a. Radiators
b. Fluorescent lighting
c. Soil and groundwater
d. Wood-burning stoves or fireplaces
e. All of the above
The answer: Soil and groundwater
Radon, a radioactive gas, is the second-leading cause of lung cancer in America and the leading cause of lung cancer in people who do not smoke. It is naturally released by minerals such as uranium and radium in well water, soil, and rock in certain areas. It is found pretty much everywhere in the air at low levels. Radon is also emitted by some building materials made from earth or stone.
When radon is in the soil beneath your house, it can waft in through cracks in the foundation, gaps in floorboards, and openings around pipes. At times, it may build up to dangerous levels. The EPA suggests that homes be treated if the measured levels of radon are above 2 pCi/L (picocuries per liter). Radon should definitely be addressed if levels exceed 4 pCi/L. But any amount of radon is potentially harmful to human health.
What you can do about radon
- Check the indoor air at the lowest floor of your home with a radon test kit. For an additional fee, the kit maker will analyze the results. Or you can have a professional do the testing. Contact the National Radon Safety Board and the National Radon Proficiency Program.
- Retest every two to five years or if you do any renovations, put in a new heating system, or install central air conditioning.
- If radon problems are detected, have them fixed promptly by a qualified radon mitigation contractor.
Identify and remove allergens
Question: Where might allergens be hiding in your home?
a. Carpets and rugs
b. Fluffy toys
c. Beds and bedding
d. Air-conditioning systems
e. All of the above
The answer: All of the above
Dust mites, pollen, dust, mold, bacteria, insects, and animal dander can trigger allergic reactions and hay fever-like symptoms in sensitive people. These irritants are everywhere, including on pets and in the bathroom. See a healthcare provider (HCP) for allergy testing if you have symptoms of allergies, including:
- Respiratory (breathing) issues
- Eye, nose, and throat irritation
- Frequent headaches
- Feeling tired or dizzy
What you can do about allergens
- Dust and vacuum your home, including upholstered furniture, frequently. Consider investing in a vacuum with a high efficiency particulate air (HEPA) filter. These can improve air quality and reduce allergens.
- Don't let moisture or humidity build up in your home. Mold and dust mites flourish in warm, damp environments. If you spot mold, remove it immediately. Try to identify the source of the moisture and fix the problem.
- Use exhaust fans in the bathroom and kitchen to help keep humidity levels low.
- If you use an air conditioner, humidifier, or dehumidifier, make sure they're well-maintained and cleaned regularly.
- Consider investing in an air purifier with a HEPA filter. These can help remove allergy causing particles from the air. If you can’t afford a store-bought HEPA filter, you can make an air purifier at home using products available for low cost at most hardware stores and major retailers. Follow these tips from the CDC to build your own air purifier.
Clear the smoke
Question: Which of the following may be a source of potentially harmful smoke?
a. Candles
b. Fireplaces
c. Wood-burning stoves
d. Gas stoves
e. All of the above
The answer: All of the above
Smoke can be an issue for indoor air, and not just from cigarettes. Though we mostly associate cozy warmth and pleasant scents with these sources of heat and flames, they also carry with them potential harms to our health. Fireplaces and both gas- and wood-burning stoves increase carbon monoxide (CO) emissions in the home. Being exposed to higher amounts of CO can cause fatigue, headaches, or trouble concentrating. (Extremely high levels can even cause death.)
When burned, candles can release small amounts of toluene, used in glues and paint thinners, and benzene, a carcinogenic (cancer-causing) gas also emitted when burning coal or oil. Toluene may cause a variety of symptoms, including irritation, dizziness, or headaches. Benzene can increase the risk of certain cancers.
What you can do about smoke
- Reduce your use of candles at home. If you do choose to use them, use them in well-ventilated areas and air out the space afterwards.
- Look for high-quality candles made from natural materials and scented with essential oils instead of synthetic fragrances. For example, choose beeswax or soy-based waxes rather than paraffin wax, which is derived from petroleum (oil). If you are sensitive to scents, choose unscented candles.
- Stay away from dyed candles, which may contain benzidine, a chemical linked to increased bladder cancer risk.
- Consider alternatives to burning candles such as oil or ghee lamps (which may have less toxicity than candles), electronic or battery-operated flameless candles, or wax melts (which use lower temperatures and put out less combustion-based chemicals and smoke)
- It may go without saying, but if you smoke tobacco products, quit. The vast majority (up to 90 percent) of benzene exposure occurs as a result of smoking
It can be overwhelming to learn that common household products may cause indoor pollution. Just know that you can control and reduce indoor air pollution risks by being a mindful consumer and practicing careful use of products. If you need to start removing certain products from your home, do so one at a time.
By gradually removing potentially dangerous products, you can begin to see improvement over time. If you suspect that chemical exposures are hampering your health, consider getting your home tested and treated and consult with a healthcare provider.
