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Region 1: EPA New England

Questions About Your Community: Indoor Air

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The average American spends approximately 90 percent of their time indoors. And while most people are aware that outdoor air pollution can damage their health, many do not know that indoor air pollutants can also do the same.

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Indoor Air Quality

Indeed, studies of human exposure to air pollutants by EPA indicate that indoor levels of pollutants may be 2 to 5 times – and occasionally more than 100 times – higher than outdoor pollutant levels. Indoor air pollutants have been ranked among the top five environmental risks to public health. The problems they cause can be subtle and do not always produce easily recognized or immediate impacts on health.

During the winter when homes, schools and office doors and windows are sealed up to conserve energy, the problem can be magnified. If too little outdoor air enters a building, pollutants can accumulate to levels that can pose health and comfort problems. Unless they are built with special mechanical means of ventilation, buildings designed to minimize the amount of outdoor air that can leak into and out of it may have high pollutant levels.

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 humidifiers; 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. Radon can enter and collect inside homes and other buildings that are not built with radon-resistant techniques. However, buildings constructed with radon-resistant techniques can ensure lower radon levels, energy efficiency, and a safer home.

Children are more susceptible to air pollution because they breathe a greater volume of air relative to their body weight. To make matters worse, schools tend to be at a higher risk of poor indoor air quality because they can have 4 times the occupants as a regular office building for the same amount of floor space and generally less maintenance making air quality in schools an area of a particular concern

Good indoor air quality (IAQ) contributes to a favorable learning environment for students, productivity for teachers and staff, and a sense of comfort, health, and welfare for school building occupants. Failure to prevent indoor air problems in schools can have serious short-term and long-term health effects.

IAQ problems are not limited to homes and schools. Many office buildings have significant air pollution sources. Some of these buildings may be inadequately ventilated. For example, mechanical ventilation systems may not be designed or operated to provide adequate amounts of outdoor air.

If you wish to learn more about indoor air pollution:

Visit EPA New England's Indoor Air Quality Web Site.

Call EPA New England's toll-free customer call center at (888) 372-7341 and ask to speak to an Indoor Air specialist.

Call the IAQ INFO toll-free line at (800) 438-4318. The IAQ INFO line is an easily accessible, central source of information on indoor air quality, created and supported by the U.S. EPA. As concern about air pollution indoors has grown, so has the amount of information on this subject; but getting current, useful information can be a challenging task. The purpose of the IAQ INFO is to help you locate information to answer your questions about indoor air pollution.

IAQ INFO can provide EPA publications on many aspects of indoor air quality including:

  • Indoor air pollutants and their sources;
  • Health effects of indoor air pollution;
  • Testing and measuring indoor air pollutants;
  • Controlling indoor air pollutants;
  • Constructing and maintaining homes and buildings to minimize indoor air quality problems;
  • Existing standards and guidelines related to indoor air quality;
  • General information on Federal and State legislation.

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