Indoor pollution sources that release gases or particles into the air are the primary cause
of indoor air quality problems in homes. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough
outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature
and humidity levels can also increase concentrations of some pollutants.
There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene,
coal, wood, and tobacco products; building materials and furnishings
as diverse as deteriorated, asbestos-containing insulation, wet
or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning
and maintenance, personal care, or hobbies; central heating and cooling
systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.
The relative importance of any single source depends on how much of a given pollutant it emits
and how hazardous those emissions are. In some cases, factors such as how old the source is and whether it is properly maintained
are significant. For example, an improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly
adjusted.
Some sources, such as building materials, furnishings, and household products like air fresheners,
release pollutants more or less continuously. Other sources, related to activities carried out in the home, release pollutants
intermittently. These include smoking, the use of unvented or malfunctioning stoves, furnaces,
or space heaters, the use of solvents in cleaning
and hobby activities, the use of paint strippers in redecorating activities, and the use of cleaning products and pesticides
in house-keeping. High pollutant concentrations can remain in the air for long periods after some of these activities.
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 preexisting 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.
Previous information obtained from www.epa.gov
