CATS: The inside scoop on inside air purifiers

Number 13 in the Clean Air Technologies Series.

If you recall, at the end of “Airing (and sharing) some thoughts about indoor air quality,” I wrote: “Incidentally, indoor air purifiers are available, but I’ve not done enough research on these so as to learn which ones add ozone to the indoor air and which do not. It’s probably worth further investigation and a follow-up report.” Well, it’s time for that follow-up report.

In presenting information, I felt it best to get and give an unbiased view. So, I consulted the California Environmental Protection Agency Air Resources Board (ARB) May 31, 2006 news release: “Some Devices Marketed as Air Cleaners Dangerous to Public Health.” In it is information worth sharing.

“Devices marketed as air cleaners or air purifiers are not always good for your health, a report to the California Air Resources Board (ARB) revealed last week,” ARB wrote in the release. “According to the report, there are devices that intentionally generate ozone, a key component of smog, resulting in indoor ozone concentrations well above health-based state and federal ambient air quality standards.”

In evaluation trials, in a small but furnished room, with atmospheric (temperature and humidity) conditions replicating those that are quite commonly encountered and, in following manufacturer instructions, the ARB’s findings were such that for all devices tested, levels of ozone emitted were above “health-based standards;” levels that “can pose a serious health risk,” according to information presented in the release. “One model produced room concentrations more than 4.5 times the health-based state ambient air quality standard for ozone. At elevated levels, ozone can exacerbate asthma, cause lung damage and lead to difficulty in breathing.”

The ARB in the release further went on to state: “Today’s report to the Board specifically covered devices that purposely generate ozone, which are marketed by manufacturers who make false health claims regarding the effectiveness and level of ozone being emitted from the device. Some manufacturers falsely claim that their products produce ‘safe’ levels of ozone that remove indoor air pollutants such as particles, gases, allergens, viruses, odorous compounds, mold, and bacteria. In fact, ozone reacts with other gases to produce significant increases in other pollutants, such as formaldehyde and ultrafine particles, which are also harmful to health, all the while deadening one’s sense of smell. In addition, ARB scientists have stated that at the levels produced by ozone generators, their emissions could hurt humans without affecting pathogens.”

The ARB offers an Indoor Air Purifier “Fact Sheet” and also has available via its Web site a page on: “Potentially Hazardous Ozone Generators Sold as Air Purifiers.”

For more, see: and

– Alan Kandel

4 thoughts on “CATS: The inside scoop on inside air purifiers”

  1. Indoor air pollution is common issue now a days. Indoor air is polluted in many ways and it causes many diseases like asthma. some air purifier devices also harmful for health. so we should be aware when buy air purifier for home.

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