From: Indoor Air Facts No. 7 - Residential Air Cleaners - http://www.epa.gov/iaq/pubs/airclean.html
Air cleaners may reduce the health effects from some particles - small solid or liquid substances suspended in air, such as dust or light spray mists.
Some air cleaners, under the right conditions, can effectively remove certain respirable-size particles (for example, tobacco smoke particles). These invisible particles are of concern because they can be inhaled deeply into the lungs. Removing such particles may reduce associated health effects in exposed people. These effects may range from eye and lung irritation to more serious effects such as cancer and decreased lung function.
Some controversy exists about whether air cleaners can reduce the allergic reactions produced by larger particles such as pollen, house dust allergens, some molds, and animal dander. Most of these particles are found where they settle on surfaces in the home, rather than in the air. They cannot be removed by an air cleaner unless disturbed and re-suspended in the air.
Air cleaners that do not contain special media, such as activated carbon or alumina, will not remove gaseous pollutants, including radon, or reduce their associated health effects. Whether air cleaners that contain these media are effective in reducing health risks from gaseous pollutants cannot be adequately assessed at this time. In addition, the effectiveness of air cleaners in reducing the health risks from radon progeny (decay products) cannot be adequately evaluated at present. The removal of gaseous pollutants and radon and its progeny is not addressed further in this fact sheet. Health effects from these pollutants may be serious, however, and they are of concern in indoor air.
- The Inside Story: A Guide to Indoor Air Quality EPA 402-K-93-007, April 1995
- Indoor Air Pollution: An Introduction for Health Professionals EPA 402-R-94-007, 1994
- Residential Air Cleaning Devices: A Summary of Available Information EPA 400/1-90-002, February 1990
- Guide to Air Cleaners in the Home EPA 402-F-07-018, October 2007
- Ozone Generators That are Sold as Air Cleaners (only available via the web site)