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Indoor Air Can Cause Health Problems

Are you worried about the air you breathe? Don't assume you're safe just because you're inside. The Environmental Protection Agency (EPA) says that the air within homes and other buildings can be more seriously polluted than the outdoor air in even the largest and most industrialized cities.

Indoor air pollution can have significant health problems. People who may be exposed to indoor air pollutants for the longest periods of time -- children, elderly adults and people with chronic illnesses -- are often those most susceptible to the effects of indoor air pollution.

Most indoor air pollution comes from sources that release gases or particles into the air. Sources such as building materials and air fresheners release pollution continuously. Other sources such as tobacco smoke and wood-burning stoves are related to activities. Although some indoor air pollutants have been around for years, they often were diluted by outdoor air seeping into the home. Today's more energy-efficient homes don't allow as much outdoor air to enter.

Indoor air hazards

Ozone generators are sold as air cleaners and intentionally produce ozone gas. High concentrations of ozone, however, react with organic material inside and outside the body. When inhaled, ozone can damage the lungs, cause chest pain, coughing, shortness of breath and throat irritation. It can make chronic respiratory diseases such as asthma worse and make people more susceptible to respiratory infections.

The EPA says that scientific research does not support claims that ozone from these devices removes dust, pollen and chemicals from the air. No federal agency has approved these devices as air cleaners. Any official number found on ozone generator packaging is not an approval number, but the designation used by the EPA to identify the specific facility that produces the product.

Other common sources of indoor pollution include:

Live sources

These include mold, mildew, cockroaches, and dust mites.

Carbon monoxide (CO)

CO and other pollutants are emitted from fuel-burning stoves, heaters, and other appliances. CO is an odorless, colorless gas that blocks the movement of oxygen in the body. Depending on how much is inhaled, CO can affect coordination, make heart conditions worse, and cause fatigue, headache, confusion, nausea and dizziness. Very high levels can cause death. Elderly adults, developing babies, and people with cardiovascular and pulmonary diseases are particularly sensitive to elevated CO levels.

Nitrogen dioxide

This is a product of natural gas and kerosene combustion. Like CO, it is odorless and colorless. It irritates the mucous membranes of the eyes, nose, and throat and causes shortness of breath in high concentrations. Long-term exposure to nitrogen dioxide can damage the lungs and may lead to chronic bronchitis. Exposure to low levels may cause an increase of symptoms in people who have asthma, a decrease in lung function in people with chronic obstructive pulmonary disease, and an increase in respiratory infections.

Sulfur dioxide

This gas is a product of burning kerosene in a space heater. It is extremely irritating to the eyes and upper respiratory tract.


Radon is a radioactive gas that seeps from the soil and rocks beneath your home. Radon can enter a home through cracks in the foundation, walls, drains and other openings. Exposure to radon in the home is the second leading cause of lung cancer; smoking is the first. Smokers and former smokers exposed to radon may have a much higher risk of death from lung cancer.

Secondhand smoke

Cigarette smoke contains trace amounts of about 4,000 chemicals, including 200 known poisons, such as formaldehyde and carbon monoxide, as well as 43 carcinogens.

These are other common household air pollutants:

  • Particulates, such as dust and pollen.

  • Formaldehyde, a common preservative and adhesive in furniture, carpets, drapes, particleboard, and plywood paneling. Breathing formaldehyde fumes can cause coughing, irritation of the eyes, nose and throat, rashes, headaches, and dizziness.

  • Household products, including personal care products, pesticides, household cleaners, solvents and chemicals used for hobbies. Exposure to these products can cause dizziness, nausea, allergic reactions, irritation of eyes, skin and lungs, and cancer. Certain cleaning products can produce toxic fumes; take care never to mix chlorine bleach and ammonia.

  • Remodeling hazards, including new carpeting and paint. These can emit fumes that irritate eyes, nose, and throat.

  • Asbestos, from insulation, floor tiles, spackling compounds, cement, and heating equipment. These products can be a problem indoors only if the material that contains the asbestos is disturbed and becomes airborne, or when the product disintegrates with age. Asbestos fibers are light, flexible and small enough to remain airborne. Because of this, fibers can be inhaled, causing scarring of lung tissue (called asbestosis) and lung cancer.

  • Lead, which was common in paint made before 1978.

  • Pesticides. Exposure to these can occur through normal use of sprays, strips impregnated with pesticides, and foggers (also called "bombs"). Exposure can also occur from contaminated dusts after use, especially for children who may be in close contact with contaminated surfaces. Symptoms can include headache, dizziness, muscular weakness, and nausea. Some pesticide may cause cancer.

Signs of air trouble

The  following symptoms may be a sign of  indoor air hazards. They include: 

  • Unusual and noticeable odors, stale or stuffy air.

  • Clear lack of air movement.

  • Dirty or faulty central heating or air conditioning.

  • Damaged flue pipes or chimneys.

  • Excessive humidity. A relative humidity of 30 to 50 percent is generally recommended for homes. Remove standing water, water-damaged materials, and wet surfaces, because these can serve as a breeding ground for molds, mildews, bacteria, and insects.

  • Molds and mildew.

  • Health reaction after remodeling, moving, weatherizing, buying new furniture, or using household or hobby products.

  • Feeling healthier outside the home.

How safe is your air?

In general:

  • Never over-buy products that might add to indoor pollution, such as cleaning solvents or pesticides.

  • Follow makers' directions for use, storage, and disposal.

  • Provide ample ventilation before and after putting in such products as pressed-wood furniture, and carpets or draperies that might emit chemicals.

  • Don't allow smoking in your house.


  • Keep moisture under control. Moisture leads to growth of living pollutants and condensation. Exhaust fans can help.

  • Personal care products and air fresheners can emit gases. Find items with little or no aerosol, open windows, and use fans.

  • Have a professional repair or remove damaged asbestos floor tiles.


  • A cold mist humidifier or vaporizer can encourage the growth of living pollutants. Use and clean the device properly and change water daily.

  • Bedding should use allergen-impermeable pillow and mattress covers. Wash regularly in water above 130 degrees F. Vacuum under beds regularly to control dust mites.

  • Dry cleaning can leave gases on clothes. Air them out before taking them indoors. Consider washing by hand instead.

  • Air conditioners harbor living allergens. Clean water trays often and change filters.

Living areas

  • Paneling or pressed-wood furniture may release formaldehyde gas. Seek brands such as those with phenol resin that emit less formaldehyde, or seal with polyurethane.

  • Carpets can emit gases when new and harbor living pollutants when wet. Air out new carpets before installing; ask for low-emitting adhesives. Clean and dry water-damaged carpets or remove them. Vacuum to curb dust mites, an asthma trigger.

  • New draperies may have a formaldehyde-based finish. Air out before hanging.

  • Fireplaces create CO and other combustion pollutants. Open the flue during use. Have the flue and chimney inspected annually.

  • Gas or kerosene space heaters create CO and combustion pollutants. Never use them unless they are adequately vented. Open doors to the rest of the house, use an exhaust fan, and open windows slightly.


  • Household cleaners may give off unsafe or irritating vapors. Use nonaerosol, nontoxic products.

  • Moisture from cooking and washing leads to living pollutants. Use exhaust fans.

  • Unvented gas stoves and ranges raise the risks of CO and combustion byproducts. Clean and adjust burners, use exhaust fans and never use a stove or range to heat a home.


  • Engine exhaust carries CO and combustion byproducts. Never run engines in a garage.

  • Paint, solvents: Ventilate when using; reseal containers well. Clean brushes outside.

  • Pesticides/fertilizers: Consider nonchemical methods. Ventilate if using indoors.

  • Fuels: Store labeled, sealed containers made for fuels outside in a well-ventilated area.

Laundry/utility areas

  • Unvented clothes dryers promote moisture, living pollutants and dust. Vent dryers to the outside. A gas-fired dryer creates CO and combustion byproducts. Clean lint filters often and provide air for gas combustion.

  • Ground moisture promotes living allergens. Look for condensation on walls, water on floors or sewage leaks. To keep water out, install gutters and downspouts, don't water near foundations, grade soil away from the house, and waterproof basement walls.

  • Asbestos pipe wrap and furnace insulation should be checked routinely for damage or wear. Have a professional make any repairs.

  • Fossil-fuel furnaces and water heaters pose risks of CO and combustion pollutants. Have them inspected yearly, clean around them often and change filters periodically. Call your fuel supplier or fire department at once if you suspect a CO or fuel leak.

  • Test for radon. Have an experienced state- or EPA-certified contractor correct radon levels of 4 picocuries per liter or higher.

For more information on indoor air safety, contact the EPA or your state-specific environmental  protection agency.