Mother Earth Living

Improve Indoor Air Quality for Better Health

From our first squall to our last gasp, we are always breathing. But the essential air we breathe can harbor serious pollutants with both short- and long-term negative health effects. We hear a lot about outside air pollutants, but in fact, federal scientists rank indoor air pollution as one of the most important environmental problems in the United States.

Americans spend about 90 percent of their time indoors. As tightly insulated and sealed buildings become more common, concentration levels of pollutants such as formaldehyde, chloroform and styrene are two to 50 times greater indoors than outdoors. Indoor air pollution can cause eye and throat irritation and headaches in the short term, and respiratory disease and cancer over time. The most sensitive people—children, pregnant women and the elderly, and those with heart and lung disease, asthma and chemical sensitivities—often spend the most time indoors. Understanding and eliminating sources of indoor air pollution can make a big improvement in your home’s overall health.

Keep your indoor air clean and healthy with these simple steps.

1. Control pollution sources. The best way to avoid indoor pollutants is to keep them out of your home in the first place.

• Banish cigarettes and pipes.
• If you have a wood stove or fireplace, clean the flue and vent to the outdoors.
• Wipe your feet on a doormat or, even better, take off your shoes at the entryway.
• Don’t use pesticides on your yard or garden. They can be tracked into your house.
• Use natural, nontoxic cleaning products such as vinegar, baking soda and borax.
• Install carbon monoxide detectors to alert you to venting problems caused by gas-burning appliances.
• Vacuum, mop and dust your home weekly. Wash bedding weekly.
• Replace carpet with washable area rugs and drapes with washable curtains or blinds.
• Use no-VOC paints and sealers. Avoid plywood or particleboard with added urea-formaldehyde or seal with a nontoxic sealer to prevent offgassing.
• Never leave your car, lawn mower or other fuel-burning appliance running in an attached garage.
2. Bring in fresh outside air with natural and mechanical ventilation. When the weather is fair, opening windows and doors throughout the house helps remove pollutants and moisture. High moisture levels in your home, especially in warm areas, can lead to mold and mildew. Interior humidity levels should be 30 to 50 percent.

• Use exhaust fans with outside vents and open windows while bathing and cooking. 
• Direct gutters and downspouts away from the house.
• If you live in a tight house in an extreme climate, consider installing a heat/energy recovery ventilator (HRV or ERV) for a constant supply of fresh air without excessive energy use.
3. Clean the air. The most effective air filters use high-efficiency particulate air (HEPA) filters similar to, but finer than, standard furnace filters. Install them in the ducts of the central heating and air-conditioning system or use portable filters with fans.

• Size portable filters appropriately to the volume of air you want to clean. Check the unit’s Clean Air Delivery Rate (CADR) at Follow the 2/3 rule: Look for the CADR listing for tobacco smoke. That number should be at least 2/3 of the room’s area. For example, a 10-by-12-foot room (120 square feet) would require a CADR of at least 80.
• Avoid electrostatic precipitators/electronic air cleaners and ion generators. They produce ozone, a lung irritant, if not maintained properly.
• Air filters require regular maintenance (usually washing or replacing filters) to work properly. Factor in the cost of replacement filters when selecting a product.

Indoor Irritant

Tobacco smoke 

Sources: Cigarettes, cigars and pipes
Potential Health Effects: Respiratory irritation, bronchitis and pneumonia in children; emphysema; lung cancer; heart diseas

Carbon monoxide 

Sources: Unvented or malfunctioning gas appliances, wood stoves, tobacco smoke
Potential Health Effects: Headache, nausea, angina, impaired vision and mental functioning; fatal at high concentrations

Nitrogen oxides 

Sources: Unvented or malfunctioning gas appliances
Potential Health Effects: Eye, nose and throat irritation; increased respiratory infections in children

Organic chemicals 

Sources: Aerosol sprays, solvents, glues, cleaning agents, pesticides, paints, moth repellents, air fresheners, dry-cleaned clothing, treated water
Potential Health Effects: Eye, nose and throat irritation; headaches; loss of coordination; damage to liver, kidneys and brain; various types of cancer


Sources: Pressed wood products such as plywood and particleboard, furnishings, wallpaper, durable press fabrics
Potential Health Effects: Eye, nose and throat irritation; headache; allergic reactions; cancer

Respirable particles 

Sources: Cigarettes, wood stoves, fireplaces, aerosol sprays, house dust
Potential Health Effects: Eye, nose and throat irritation; increased susceptibility to respiratory infections and bronchitis; lung cancer

Biological agents (bacteria, viruses, fungi, animal dander, mites) 

Sources: House dust; pets; bedding; poorly maintained air conditioners, humidifiers and dehumidifiers; wet or moist structures; furnishings
Potential Health Effects: Allergic reactions; asthma; eye, nose and throat irritation; fever; influenza; other infectious diseases


Sources: Damaged or deteriorating insulation, fireproofing and acoustic materials
Potential Health Effects: Asbestosis, lung cancer, mesothelioma, other cancers


Sources: Sanding or open-flame burning of lead paint, house dust
Potential Health Effects: Nerve and brain damage, particularly in children; anemia; kidney damage; growth retardation


Sources: Soil under buildings, some earth-derived construction materials, groundwater
Potential Health Effects: Lung cancer

Kelly Lerner is a Spokane, Washington-based, award-winning architect specializing in healthy, beautiful, energy-efficient homes. She is co-author of Natural Remodeling for the Not-So-Green Home. See her work at and 

  • Published on Dec 8, 2010
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