- Indoor air quality can be worse than that of outdoor air.
- Problems can arise from moisture, insects, pets, appliances, radon, materials used in household products and furnishings, smoke and other sources.
- Effects range from minor annoyances to major health risks.
- Remedies include ventilation, cleaning, moisture control, inspections, and following manufacturers' directions when using appliances and products.
- Research has shown that the quality of indoor air can be worse than that of outdoor air. Many homes are built or remodeled more tightly, without regard to the factors that assure fresh and healthy indoor air. Our homes today contain many furnishings, appliances and products that can affect indoor air quality.
Signs of indoor air quality problems include:
- Unusual and noticeable odors.
- Stale or stuffy air.
- Noticeable lack of air movement.
- Dirty or faulty central heating or air conditioning equipment.
- Damaged flue pipes or chimneys.
- Unvented combustion air sources for fossil fuel appliances.
- Excessive humidity.
- Presence of molds and mildew.
- Health reaction after remodeling, weatherizing, using new furniture, using household and hobby products, or moving into a new home.
- Feeling noticeably healthier outside.
Common Sources of Air Quality Problems
Poor indoor air can arise from many sources. At least some of the following contaminants can be found in almost any home:
- Moisture and biological pollutants such as molds, mildew, dust mites, animal dander and cockroaches from high humidity levels, inadequate ventilation, and poorly maintained humidifiers and air conditioners.
- Combustion products, including carbon monoxide, from unvented fossil fuel space heaters, unvented gas stoves and ovens, and backdrafting from furnaces and water heaters.
- Formaldehyde from durable press draperies and other textiles, particle board products such as cabinets and furniture framing, and adhesives.
- Radon, a radioactive gas from soil and rock beneath and around the home's foundation, groundwater wells and some building materials.
- Household products and furnishings such as paints, solvents, air fresheners, hobby supplies, dry-cleaned clothing, aerosol sprays, adhesives, and fabric additives used in carpeting and furniture which can release volatile organic compounds.
- Asbestos found in most homes more than 20 years old. Sources include deteriorating, damaged or disturbed pipe insulation, fire retardant, acoustical material and floor tiles.
- Lead from lead-based paint dust created when removing paint by sanding, scraping or burning.
- Particulates from dust and pollen, fireplaces, wood stoves, kerosene heaters and unvented gas space heaters.
- Tobacco smoke, which produces particulates, combustion products and formaldehyde.
Indoor Air Pollution and Health
Health effects from indoor air pollutants may be experienced soon after exposure or, possibly, years later.
Immediate effects may show up after a single exposure or repeated exposures. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. Sometimes the treatment is simply eliminating the person's exposure to the source of the pollution, if it can be identified. Symptoms of some diseases, including asthma, hypersensitivity pneumonitis, and humidifier fever, may also show up soon after exposure to some indoor air pollutants.
The likelihood of immediate reactions to indoor air pollutants depends on several factors. Age and pre-existing medical conditions are two important influences. In other cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological pollutants after repeated exposures, and it appears that some people can become sensitized to chemical pollutants as well.
Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place symptoms occur. If the symptoms fade or go away when a person is away from home, for example, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air or from the heating, cooling, or humidity conditions prevalent in the home.
Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease, and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable.
While pollutants commonly found in indoor air are responsible for many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. People also react very differently to exposure to indoor air pollutants. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes and which occurs from the higher concentrations that occur for short periods of time.