Ionic filters are constantly rated by Consumers Reports as "not acceptable" due to the fact that emit unacceptable amounts of ozone and allow unacceptable amounts of particles though.
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Buying an air cleaner that doesn't clean the air is bad enough. Some of the least effective ionizer models also can expose you to potentially harmful ozone levels, especially if you're among the roughly 80 percent of buyers with asthma or allergy concerns.
Also known as electrostatic precipitators, the five ionizing air cleaners we focused on for this report are supposed to trap charged particles on oppositely charged plates. But as we reported in our October 2003 report on air cleaners, models like Sharper Image's Ionic Breeze, the market leader, did a poor job removing dust and smoke from the air. Our latest tests also show that some ionizing models can expose you to significant amounts of ozone.
Unlike ozone in the upper atmosphere, which helps shield us from harmful ultraviolet rays, ozone near ground level is an irritant that can aggravate asthma and decrease lung function. Air cleaners need not meet ozone limits--not for the federal Environmental Protection Agency, which regulates only outdoor air, nor for the Food and Drug Administration, since it doesn't consider them medical devices, despite the health benefits that some ads imply. (See Air cleaners: The truth behind the accolades.) Manufacturers often submit air cleaners to a voluntary standard that includes a test to see whether they produce more than 50 parts per billion (ppb) of ozone, the same limit the FDA uses for medical devices.
We replicated that test using the sealed polyethylene room specified by Underwriters Laboratories Standard 867 to help ensure consistent results. Ozone levels were measured 2 inches from each machine's air discharge in accordance with the standard. All five ionizers failed the test by producing more than the 50-ppb limit--in some cases, much more.
People don't live in sealed plastic rooms, however. So we also tested these ionizing air cleaners in an open, well-ventilated lab. For comparison, we also tested a top-performing Friedrich electrostatic-precipitator and a Whirlpool HEPA model from previous reports.
We measured ozone levels 2 inches from the machines, as in the sealed-room test, and 3 feet away, since ozone becomes diluted and dissipates rapidly indoors as it reacts with carpet, upholstery, and other surfaces. In our lab tests, two ionizing models--the IonizAir P4620 and the Surround Air XJ-2000--emitted more than 150 and 300 ppb, respectively, 2 inches from the machine.
The bottom line: Consumers Union believes that the CPSC should set indoor ozone limits for all air cleaners and mandate performance tests and labels disclosing the results. CU also believes that the Federal Trade Commission should take a close look at air-cleaner ads to determine whether they include unsubstantiated and deceptive claims.
In the meantime, we recommend avoiding ionizers that performed poorly or emitted significant ozone in our tests. We can't guarantee safety at any ozone level, so it makes sense not to contaminate your living space, says Jonathan Samet, M.D., chairman of the epidemiology department of the Johns Hopkins Bloomberg School of Public Health.
Buy any good HEPA filter and you will much better off.
Good Luck