Particles and Air Cleaners

This page last reviewed April 2, 2012

Reducing Exposure to Particulate Pollutants

Particulate pollutants are found both indoors and outdoors. They include very small (often invisible) particles from combustion sources such as motor vehicle exhaust, cigarette smoke, cooking, and woodburning activities; biological components such as pollen and mold spores, and dust mite allergens; and fine fibers such as asbestos. Particulate pollutants can cause a variety of harmful health effects. These effects include cough, nasal irritation, lung infection, allergy symptoms, asthma, chronic lung conditions, cancer, and premature death. There are many actions you can take to reduce your and your family's exposure to particulate pollutants.

image of red arrow with the word go "Reducing Your Exposure to Particulate Pollutants" (Fact Sheet)

Air Cleaners

The most effective way to reduce exposure to indoor pollutants is to first remove sources of pollution or reduce pollutant emissions. A second important action is to provide adequate ventilation. If these actions do not resolve indoor air quality problems, sensitive individuals may benefit from using a central air filter or a good air cleaner in one or more rooms of the house. Air filters and air cleaners can only be effective if they are properly maintained.

How to Select a Safe and Effective Air Cleaner

image of red arrow with the word go "Air Cleaning Devices for the Home, Frequently Asked Questions" (ARB Fact Sheet, Feb. 2005)

image of red arrow with the word go "Air Purifiers: Filtering the Claims," Consumer Reports, December 2007, Issue 12, pages 48-51. Posted with permission; for educational purposes only.

image of red arrow with the word go Clear Air Delivery Rates (CADR) of Many Air Cleaners - Association of Home Appliance Manufacturers (AHAM)

This links to the Association of Home Appliance Manufacturers (AHAM) website that lists the clean air delivery rates (CADR) of many air cleaners. CADR is a measure of the air cleaner's ability to reduce smoke, dust, and pollen particles from the air.

Air Cleaners to Avoid

Not all air-cleaning devices are appropriate for home use — some can be harmful to human health. The ARB recommends that ozone generators, air cleaners that intentionally produce ozone, not be used in the home. Ozone is a gas that can cause health problems, including respiratory tract irritation and breathing difficulty (Ozone and Health).

image of red arrow with the word go List of Potentially Hazardous Ozone Generators Sold as Air Purifiers (November 6, 2007)

image of red arrow with the word go Fact Sheet: Beware of Ozone-Generating Indoor "Air Purifiers" (March 2006)

For more information on ozone generating air cleaners, please visit our website at Hazardous Ozone-Generating "Air Purifiers"

Combustion Pollutants

The guidance document below provides information on the sources and health effects of indoor combustion pollutants and discusses actions you can take to reduce your exposures to them.

image of red arrow with the word go Combustion Pollutants in Your Home - Guideline No. 2 (html) or (PDF - 8 MB)

image of red arrow with the word go Combustion Pollutants in Your Home - Supplement to Guideline No. 2

Other Sources of Air Cleaner Information

The final research report below discusses the results of a survey of 2019 Californians on their use of air cleaning devices.

image of red arrow with the word go "Survey of the Use of Ozone-Generating Air Cleaners by the California Public"
(Final Research Report January, 2007)

The Lawrence Berkeley National Laboratory has produced a multi-page summary of research results on the effectiveness, cost, and health benefits of filtration, which is linked below.

image of red arrow with the word go Filtration for Particles