Humidifiers
Humidifiers are commonly used in homes to relieve the physical discomforts of dry nose, throat, lips, and skin. The moisture they add to dry air also helps alleviate common nuisances brought on
by winter heating, such as static electricity, peeling wallpaper, and cracks in paint and furniture. However, excess moisture can encourage the growth of biological organisms in the home. These organisms include dust mites, which are microscopic animals that
produce materials causing allergic reactions to household dust, and molds.
Studies by the Environmental Protection Agency (EPA) and the Consumer Product Safety Commission (CPSC) have shown that ultrasonic and impeller (or "cool mist") humidifiers can disperse
materials, such as microorganisms and minerals, from their water tanks into indoor air. At present, only limited information is available on the growth of microorganisms and the dispersal of microorganisms and minerals by home humidifiers.
Proper care and cleaning of ultrasonic and impeller humidifiers are important for reducing potential exposures to microorganisms, such as bacteria and molds. Microorganisms often grow in humidifiers
which are equipped with tanks containing standing water. Breathing mist containing these pollutants has been implicated as causing a certain type of inflammation of the lungs.
The Federal government has not concluded that the dispersal of minerals by home humidifiers poses a serious health risk. Nevertheless, using water with lower mineral content will reduce exposures
to these materials.
The young, the elderly, and those people with lung diseases or respiratory allergies may be particularly susceptible to certain types of airborne pollutants. However, if you follow the recommendations
for the use and care of home humidifiers provided in this fact sheet, the potential for dispersal of microorganisms and minerals from your humidifier should be reduced.
Air Cleaners
Indoor air pollutants are unwanted, sometimes harmful materials in the air. They range from dusts to chemicals to radon. Air cleaners are devices that attempt to remove such pollutants from the indoor air you breathe.
The typical furnace filter installed in the ductwork of most home heating and/or air-conditioning systems is a simple air cleaner. This basic filtering system may be upgraded by using another filter
to trap additional pollutants or by adding additional air-cleaning devices. An alternative to upgrading the induct air cleaning system is using individual room, portable air cleaners. Air cleaners generally rely on filtration, or the attraction of charged particles
to the air cleaning device itself or to surfaces within the home, for the removal of pollutants. The use of "air cleaning" to remove pollutants from the air in residences is in its infancy; this publication presents the current state of knowledge.
This publication describes the types of air cleaners available to the consumer, provides available information on their general effectiveness in removing indoor air pollutants, discusses some factors
to consider in deciding whether to use an air-cleaning unit, and describes existing guidelines that can be used to compare units. It does not discuss the effectiveness of air-cleaning systems installed in the central heating, ventilating, and air-conditioning
(HVAC) systems of large buildings, such as apartment, office, or public buildings, nor does it evaluate specific products.
Because many factors need to be considered in determining whether use of an air cleaner is appropriate in a particular setting, the decision whether or not to use an air cleaner is left to the individual.
EPA has not taken a position either for or against the use of these devices in the home.
