Is air pollution being produced and distributed in your home?

Unfortunately, often the answer is yes.

Just as uncontrolled industrial processes can foul the air outside, many of industrial products, wonderful as they are, can contribute to air pollution in our homes. The process of cooking, as well as heating and cooling our homes, can also add to indoor pollution.

And this pollution can be trapped indoors. In past years, our need to save energy encouraged us to conserve it where we could. So we made our houses airtight, adding storm windows and insulation. We applied weather stripping and caulking to seal cracks, and have increasingly turned to kerosene, wood and coal to help heat our homes. However, we have often ignored the effects of these measures on indoor air quality. As a result, researchers have found air pollution can be much greater inside the home than outside.

On average we spend about 90 percent of our time indoors - out of that 90 percent, 65 percent is spent at home.

The people who are especially susceptible are the very ones who spend the most time at home. Children, pregnant women, the elderly, and people with lung disease -- these become the major victims of indoor air pollution.

What's worse, like so much air pollution, many of the contaminating substances give no warning and produce vague and sometimes similar symptoms that are hard to pin down to a specific cause or produce symptoms years later, when it's even harder to discover the cause.

Based on research already done on industrial and outdoor air pollution, and more recent research on a variety of indoor pollutants, we can identify many harmful substances.

We know the effects they can have and many of their sources. In many circumstances, we can take responsibility for the quality of air in our own homes.

Major Indoor Air Pollutants

Many viruses, bacteria, molds, fungi and microscopic mites are common, even inevitable, indoor air pollutants.
Major Sources
Fungi and other microbes can be carried indoors by people and find nourishment in improperly maintained air conditioners, humidifiers, dehumidifiers, and air-cleaning filters. Plants, pets and pests are also potential sources of indoor allergens. High humidity levels indoors encourage the growth of microscopic dust mites, molds and mildew.
Health Effects
A host of illnesses and diseases may be cultivated in the circumstances just described. Humidifier fever is an example of such cultivated pollution. People with a particular sensitivity to even non-disease causing irritants such as dust mites or animal hair can experience reactions ranging from discomfort to severe illness.

Major Sources
Despite growing recognition of the fact that smoking causes health problems, many people continue to smoke. Smokers not only endanger themselves, but others as well, through "secondhand smoke"- the smoke a person may inhale from someone else's cigarette, cigar, or pipe. This kind of smoke contains carbon monoxide, formaldehyde, and many other gases and particles, several of which are known to cause cancer.
Health Effects
Secondhand smoke has been classified as a Group A carcinogen by the U.S. Environmental Protection Agency, a rating used only for substances proven to cause cancer in humans. It is responsible for approximately 3,000 lung cancer deaths annually. Secondhand smoke is a direct health threat to people who already have heart and lung disease, and increases the risk of serious respiratory disease during the first two years of a child's life. Secondhand smoke contributes to 150,000 - 300,000 lower respiratory tract infections annually in children younger than 18 months of age, resulting in 7,500 - 15,000 hospitalizations.

This gas, an outdoor air pollutant, can also be commonly found in the home. Researchers have found that concentrations of nitrogen dioxide in the home result from both outdoor sources and unvented indoor combustion sources. In some homes, indoor NO2 levels have been found to be much higher than outdoor levels.
Major Sources
If venting and maintenance are not adequate, gas appliances (ranges, water heaters, clothes dryers, etc.), fireplaces, and wood and coal stoves can emit troubling amounts of nitrogen dioxide.
Health Effects
Nitrogen dioxide can contribute to eye and respiratory tract irritation and lower resistance to respiratory infection. Prolonged exposure to high levels of this gas can damage respiratory tissue and may lead to chronic bronchitis.

Carbon monoxide is an odorless, colorless gas that also frequently pollutes the outdoor air. Some homes have been found to have concentrations of this gas that are above the federal health standard set under the Clean Air Act for one hour exposure to outdoor air.
Major Sources
Carbon monoxide comes from the same indoor sources as nitrogen dioxide. It is also emitted by other combustion sources such as burning charcoal, gasoline engines running in attached garages or sheds, unvented kerosene heaters, and tobacco smoke.
Health Effects
Carbon monoxide interferes with the distribution of oxygen to the body. Depending on the amount inhaled, this gas can impede coordination, worsen cardiovascular conditions, and produce fatigue, headache, confusion, nausea, and dizziness. Very high levels can cause death.

This gas, which has a strong, unpleasant smell, can cause health problems in the home. The process by which formaldehyde gas is released from formaldehyde-containing products is speeded up by high temperature and humidity.
Major Sources
Formaldehyde is found in dozens of household products and in cigarette smoke. The major sources in the home are the resins in particleboard, fiberboard, and plywood panelling; and some adhesives, carpet backing, upholstery, and drapery fabric. Though no longer widely used, up until the early 1980s urea-formaldehyde foam insulation was a significant source of formaldehyde problems in many homes. In 1986, the U.S. Department of Housing and Urban Development required manufacturers of pressed wood products to formulate low formaldehyde emitting products for use in mobile homes, where use of pressed wood products for construction is often widespread.
Health Effects
Formaldehyde gas can cause headaches, dizziness, lethargy, rashes, nausea, and irritation of the eyes and upper respiratory tract. Lengthy exposure at high levels may be related to nasal cancer. High levels may trigger an asthma episode (attack) in people with asthma, and can result in some people having permanent sensitization to even low levels of formaldehyde.

This radioactive gas is given off by soil or rock with trace amounts of uranium or radium, as these elements decay. Concentrations of radon inside the home can range from relatively low outdoor levels to hundreds of times as much.
Major Sources
The major source of high levels of radon in homes is soil surrounding the house, particularly uranium-containing soil such as granite, shale, phosphate and pitchblende. Radon gas from the soil can enter into a home or building through cracks in the foundation floor and walls, drains, sumps, joints, or other openings. Radon problems have been identified in every state. The U.S. Environmental Protection Agency (EPA) estimates that nearly 1 out of every 15 homes in the United States has radon levels above EPA's recommended action level of 4 picocuries per liter.
Health Effects
Indoor radon exposure is estimated to be the second leading cause of lung cancer, responsible for thousands of deaths each year in the United States. Exposure to radon in combination with cigarette smoking significantly increases the risk of lung cancer. Therefore, for smokers, exposure to radon is a particularly serious health risk.

The name asbestos is given to a group of microscopic mineral fibers that are flexible, durable, and that will not burn. Asbestos fibers are light and small enough to remain airborne for long periods of time.
Major Sources
Many of the thousands of asbestos products are found in the home -- in roofing and flooring materials, wall and pipe insulation, spackling compounds, cement, coating materials, heating equipment, and acoustic insulation. However, they are rarely a problem indoors unless the asbestos-containing material is disturbed, or until it disintegrates with age.
Health Effects
Asbestos fibers are small enough to be inhaled into the lungs and are long-lasting, even within human tissue. As a result, asbestos can cause asbestosis (scarring of the lung tissue), lung cancer and mesothehoma, a relatively uncommon cancer of the lining of the lung or abdominal cavity.

Major Sources
In spite of the listing of ingredients and clearly marked warnings on many products, people often use cleaning agents, personal care products, pesticides, paints, hobby products and solvents without bothering to read the labels on the products. Potassium hydroxide, perchloroethylene, methylene chloride, mercury, paradichlorobenzene, and lead arsenate are just a few of the multitude of potentially harmful chemicals found in these items. The average home contains some 45 aerosol products alone, and aerosol particles, which can carry many of these toxic compounds with them, are small enough to bypass the lungs' defenses.
Health Effects
The harmful components in many of these household and personal care helpers can cause dizziness, nausea, allergic reactions, and eye, skin, and respiratory tract irritation.