Butte County Air Quality Management District
629 Entler Avenue, Suite 15
Chico, CA 95928
(530) 332-9400

Health Advisories

Butte County Air Quality Management District issues Advisories during periods of unhealthy air quality.


There is a Joint Air Quality Advisory in effect for Septmber 22 and 23, 2014 issued by the Butte County Air Quality Management District and Butte County Public Health Department regarding smoke impacts from the King Fire.


Air Cleaners Alert

Consumers should not use indoor air cleaners that generate ozone, warns California Air Resources Board. See all the information, including factsheets, information on health effects, a list of air cleaners to avoid, and a list of certified air-cleaning devices at

In 2007, the California Air Resources Board (ARB) approved a regulation to limit ozone emissions from indoor air cleaning devices.  Beginning October 18, 2010, no person or business may manufacture, sell, supply, offer for sale or introduce into commerce, for use in California, any indoor air cleaning device for use or intended for use in occupied spaces unless the device is certified by the ARB to produce an ozone emission concentration that does not exceed 0.050 parts per million. Manufacturers and sellers have until that date to have their products tested by designated laboratories and certified by the ARB.

Until October 18, 2010, manufacturers may sell indoor air cleaners that generate potentially harmful levels of ozone to California residents. ARB recommends avoiding ozone-generating indoor air cleaners.

ARB staff reported the results from multiple studies of ozone- generating machines. These devices purposely emit ozone, the major component of smog, to clean the air. One study, conducted by the USEPA, ran an ozone generator in a test home at its maximum setting. When the room's air was sampled, ozone levels were found exceeding 0.3 parts per million (ppm), and an adjacent room's levels exceeded 0.2 ppm. This level is equal to a stage one smog alert when local air pollution control districts advise the public to avoid some outdoor activities. These readings far exceed the state's ambient one-hour standard for ozone of 0.09 ppm, and any recently observed outdoor peak levels in California. At the machine's medium setting, even with the home's central fan turned on, ozone levels still exceeded the state standard. These findings force the Board to recommend the public avoid using these devices.

ARB scientists expressed concern, since some manufacturers aggressively market these products to individuals with asthma and other respiratory and health problems. Ozone can damage the cells lining nasal passages and lungs making it difficult to breathe and can exacerbate asthma symptoms. At the ozone levels noted above, some people would experience reductions in lung function, particularly if they engage in significant indoor activity (ie., housework, use of exercise equipment, children in active play), as well as symptoms such as pain on deep breath, cough and chest tightness. Elevated ozone levels can also damage household materials, such as carpeting and paint, as well as react indoors to form increased levels of formaldehyde and ultra-fine particulate matter; with their compounding negative health effects. If a family were to leave these machines on constantly, it would be as though the family lived in a 24 hour/seven day a week stage-one smog alert.

With public concern about indoor air quality rising, advertising and sales of these devices is increasing. Manufacturers often falsely claim that these devices eliminate bacteria, mold, and chemical contaminants from the air, and that they help persons with asthma and allergies. Independent studies by the USEPA, the Consumers Union, and others have shown that these devices do not effectively destroy microbes, remove odor sources, or reduce indoor pollutants enough to provide any health benefits. Ozone masks the odor of other indoor pollutants by deadening the sense of smell. Although ozone is used effectively in water to destroy microbes, ozone in air must reach extremely hazardous levels (50-100 times the outdoor air quality standards) to effectively kill microbes.

For more information, see