Healthy Indoor Air for America's Homes
Combustion Pollutants

To protect yourself and your family from combustion pollutants, you need to know whether
you're at risk. Here are some common questions and answers.

Q: What are combustion pollutants?
A: They include gases or particles that come from smoking and the burning of fuels--natural gas, propane, wood, oil, kerosene and coal. The resulting harmful gases include carbon monoxide, nitrogen dioxide, sulfur dioxide, particulates and excess water vapor.

Q: Why should I be concerned about them?
A: Carbon monoxide, an odorless gas, can be fatal. Nitrogen dioxide can damage the respiratory tract, and sulfur dioxide can irritate the eyes, nose and respiratory tract. Smoke and other particulates irritate the eyes, nose and throat, and can cause lung cancer. Too much water vapor can lead to moisture problems in the home, including the growth of mold.

Q: How do combustion pollutants get into the home?
A: Combustion pollutants enter the home from a variety of sources. Any heating appliances that burn fuels--furnaces, boilers, water heaters, fireplaces, stoves, space heaters, ranges and clothes dryers--introduce combustion gases. These pollutants also are caused by tobacco smoking, automobile exhaust entering from a garage, and activities involving the use of internal combustion engines or burning, welding or soldering.

Q: What causes these gases (including carbon monoxide) to build to dangerous levels?
A: Harmful build-ups of these gases can occur when: exhaust from combustion equipment is not properly vented or used,is not in good working order and is not regularly inspected for safe operation.

Some homes may have a problem with "backdrafting." That's when the air pressure inside the home is less than the air pressure outside, causing combustion by-products from furnaces, water heaters, fireplaces and similar equipment to spill back into the room rather than being vented outside. (Sometimes flue gases can be drawn back into the home when several sources are being exhausted at once.) Backdrafting can also occur when natural draft appliance exhaust is pulled back into the house by mechanical ventilation-like a down-draft kitchen power vent. Tobacco smoking inside home also contributes.

Q: How can I determine if combustion pollutants are affecting my health?
A: They may be the culprit if fuel-fired combustion appliances are being used and only when you're inside the home and the symptoms disappear when you leave, or if more than one person in the home has similar symptoms. A noticeable increase in moisture problems can also be a sign of combustion pollutants in the home.

Q: How can I reduce the risk from combustion gases?
A: The most important practice is to keep all combustion equipment well-maintained and inspected for safety. Experts recommend having your combustion heating systems inspected by a trained professional every year. Such inspections should look for blocked openings to flues and chimneys; cracked or disconnected flue pipe; dirty filters; rust or cracks in the heat exchanger; soot or creosote build-up; and exhaust or gas odors. Also, always operate combustion equipment for its intended purpose and make sure it has been installed correctly.

consider using vented appliances whenever possible. You should install a carbon monoxide alarm, which will alert you to dangerous levels of carbon monoxide-though not detect other combustion by-products. choose one wisely and keep it in good working order.

Q: What can I do to reduce formaldehyde problems?
A: In most cases, formaldehyde does not penetrate completely sealed plastic laminate and is at least partly blocked by coatings. Varnishes and special formaldehyde sealants are also available. Apply these coatings to all exposed edges and surfaces, such as the undersides of countertops, cabinet interiors and drawers.

High humidity and elevated temperatures cause formaldehyde release, so you might want to control humidity through air conditioning and properly used and maintained dehumidifiers. Also, increase ventilation, particularly after bringing new sources of formaldehyde into the home. When remodeling and in new construction, select low formaldehyde materials.

Q: What about other chemical products used in remodeling, such as paints, wood strippers and finishes, adhesives, waxes and cleaners?
A: The products to watch for are those containing volatile organic compounds, which are organic solvents that easily evaporate into the air. Some may be flammable. Following are some of the potentially hazardous compounds listed on product labels: petroleum distillates, mineral spirits, chlorinated solvents, carbon tetrachloride, methylene chloride, trichloroethane, toluene and formaldehyde. Other remodeling products can be hazardous if they are used improperly.


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