SACRAMENTO - The California Air Resources Board is warning consumers this holiday season to not purchase air purifiers or air cleaning devices that intentionally generate ozone.

Consumers may unknowingly purchase these "ozone generators" from advertisers touting the so-called benefits of "activated oxygen" that can make the air inside your home "as fresh as the outdoors after a thunderstorm." Ozone, a well-known component of smog, has been extensively studied and the harmful effects well documented.

"Consumers should take care when considering purchase of an air cleaning device," said ARB Chairman Mary Nichols, "Beware of misleading advertisements offering air purifiers that are simply indoor smog-making machines."

Ozone generators are capable of emitting enough ozone indoors to far exceed outdoor health standards and can intentionally create the equivalent of a Stage 1 smog alert inside your home. These devices pump a well-known air pollutant into people's homes putting everyone at risk, especially the most vulnerable among us, including the young, elderly and infirm.

The devices can produce potentially harmful levels of ozone that can worsen asthma, cause serious lung inflammation, decrease lung function, and lead to hospitalization for respiratory conditions, emergency room visits for asthma, and increased school absences.

Recently the sale of these devices became regulated by the ARB in order to protect public health. Air cleaners are currently being tested to assure they do not emit harmful levels of ozone; however, testing of air cleaners by certified laboratories is expected to take up to two years, during which time high ozone-emitting devices can still be sold. For that reason, the ARB recommends consumers avoid the purchase of any air cleaner for home or office that intentionally emits ozone.

The best and most effective way to avoid indoor air pollution problems is to remove the sources of the pollution or prevent emissions to begin with. Improving fresh-air ventilation is also helpful. Information on these approaches (https://ww3.arb.ca.gov/research/indoor/indoor.htm)

Persons still wishing to use an air cleaner should look for models that use high-efficiency pleated filters, known as HEPA filters, or electrostatic precipitators that do not emit high amounts of ozone. Guidance for selecting air cleaners (https://ww3.arb.ca.gov/research/indoor/ozone.htm), including ratings in Consumer Reports articles and ARB's fact sheet entitled "Air Cleaning Devices for the Home: Frequently Asked Questions,"

list of air cleaners (https://ww3.arb.ca.gov/research/indoor/o3g-list.htm).

More information about ozone-emitting air cleaners (https://ww3.arb.ca.gov/research/indoor/o3g-list.htm) and the Air Resources Board regulation.