Note: when the need for an air cleaning is brought to your attention by someone selling the device, the buyer should consider doing more research to determine the need and effectiveness of the device. In other words, buyer beware. Base your purchase on an objective opinion.
A number of “Portable Air Cleaners” are sold by the big box retailers, hardware stores, department stores, and over the internet. These types of air cleaners are useful, to some extent, for cleansing a number of unwanted indoor pollutants from the air. Generally, pollutants can be categorized as one of two types:
particles (mist, dust, pollen, animal dander, viruses, bacteria, and some molds),
gaseous pollutants (combustion gases, smoke, off gassing from building materials, adhesives and paints, and cleaning supplies)
Most air cleaners on the market purchased by residential property owners use filtration as the method for extracting pollutants from the air. Other methods include Electronic Air Cleaners which use an electrical field to trap charged particles on electrically charged plates, and Ion Generators which use static charges to trap and remove pollutants from the air.
The performance of a portable air cleaner depends on a number of factors, including:
The amount of air flowing through the air cleaner.
The type and efficiency of the filter.
The quality of construction which affects particle and air-bypass around the filter.
The amount of particles present in the air.
The size of particles present in the air.
The amount and type of gasses present in the air.
The room conditions such as air temperature and humidity which affect the capacity of adsorbents to remove odors and chemicals.
Placement of the unit in the room.
Portable Air Cleaners Are Not Recommended for Radon
Portable air cleaning devices are not effective at reducing radon levels in a building. If a high level of radon is present in an existing home, the method most often used to reduce levels is a vent pipe system and fan. This method pulls radon from beneath the house and vents it to the outside. In new homes, builders can easily include radon-resistant features during construction at a reasonable cost, and home buyers should ask for these. For more information about radon, visit the Maine Radiation Control Program at www.maineradiationcontrol.org.
Even though you can’t see or small radon gas, it is easy to test for it in your home or building. There are low-cost, "do-it-yourself" radon test kits you can get through the mail. Kits are available to test for radon in the air or to test for radon in your water supply. There are Indoor Air Quality professionals or home inspectors you can hire to do the testing for you. Visit our link on the Maine Indoor Air Quality web site at www.miaqc.org/Sleuth%20-%20Radon.htm for more information.
Recommendations for use of Portable Air Cleaners
Air cleaners alone are not effective in the complete removal of air pollutants. Try to eliminate the source of the pollutant and/or introduce clean, outside air to the space. Portable air cleaners are not whole house air cleaners. They can be used effectively in individual rooms, such as bedrooms or playrooms. For example, air purifiers can be effective to reduce exposure to cat or dog allergens in a bedroom or other specific area of a home. Air purifiers can also be effective in reducing unavoidable odors. Air cleaners are not generally recommended for dust mite reduction, as the breeze generated stirs up more mite allergen than it removes. It is important to follow the manufacturers’ instructions and guidelines for use. Portable air cleaners which use filtration as the method of extracting pollutants from the air may use High Efficiency Particulate Air (HEPA) filters. These filters have a greater effectiveness over other types of flat or pleated filters.
Electronic Air Cleaners and Ion Generators may emit ozone into the indoor environment. This type of product is not recommended. Ozone can be harmful to health. When inhaled, ozone can damage the lungs. Low amounts of ozone can cause shortness of breath, throat irritation, coughing, and chest pain. It may also worsen asthma and other respiratory diseases and weaken the bodies ability to fight respiratory infections. The EPA has accumulated information about air cleaners that produce ozone and their effect on health. For more information about ozone generators, visit: Ozone Generators That Are Sold As Air Cleaners: An Assessment of Effectiveness and Health Consequences.
Property owners considering purchasing a portable air cleaner should carefully research the product being considered. The U.S. EPA web site has compiled information in an easy to read publication that can be found on-line. It is useful in determining what product will safely accomplish the desired air cleaning task. Not all products are the same and there are risks and benefits of each. As always, follow all of the manufacturer’s recommendations for safe use and operations of the product.
Standards for Portable Air Cleaners
The Association of Home Appliance Manufacturers (AHAM) administers a voluntary Room Air Cleaner Certification Program for portable household electric room air cleaners. This standard outlines the room air cleaner effectiveness by the clean air delivery rate (CADR) for each of the three types in indoor air pollutants: tobacco, dust, and pollen. Information on the certification program can be found at the AHAM web site. The state of California has also done a significant amount of work to identify and regulate unsafe air cleaning devices. For information about this regulation and additional guidelines for picking a safe and effective air cleaning device for your home, visit: http://www.arb.ca.gov/research/indoor/ozone.htm
Web Links for Additional Information
U.S. EPA – wide variety of information on indoor environmental pollutants and tips for addressing them, visit: www.epa.gov/iaq.
American Lung Association – for information on asthma and general lung health, visit: www.lungusa.org.
California Environmental Protection Agency Air Resources Board: http://www.arb.ca.gov/research/indoor/ozone.htm Contains information about specific ozone generating devices, plus Q & A fact sheets and other air cleaning information.