The May issue of Consumer Reports presents new concerns about ionizing air cleaners: among five models that did a poor job of cleaning the air, several can expose users to potentially harmful ozone levels.

Months of unbiased testing and expert investigation demonstrate why the five ionizing models with poor performance, including those with relatively high ozone generation, are not recommended.

Ozone from ionizing air cleaners is a growing concern as sales increase. People with asthma or respiratory allergies are especially sensitive to indoor ozone, an irritant that can worsen asthma, deaden sense of smell, raise sensitivity to pollen and mold, and may cause permanent lung damage.

CR tested ionizing air cleaners for ozone levels and for their ability to remove dust, cigarette smoke, and pollen from the air. According to CRs independent test results, the following models are not recommended because they perform poorly and emit relatively high levels of ozone:

• Brookstone Pure-Ion V2;
Sharper Image Professional Series;
• Ionic Breeze Quadra S1737 SNX;
• Ionic Pro CL-369; IonizAir P4620; and
• Surround Air XJ-2000.

All five ionizers failed the industry standard sealed-room test for ozone levels replicated for this report by producing more than 50 parts per billion (ppb) of ozone near the machine. This limit is used by manufacturers who submit their air cleaners to a voluntary standard that includes a test to measure ozone levels in a sealed room.

In further CR tests within a well-ventilated open lab, the IonizAir P4620 and the Surround Air XJ-2000 emitted more than 150 and 300 ppb of ozone, respectively, near the machine. While readings were far lower 3 feet away, consumers could be exposed to higher ozone levels than those CR measured at 3 feet if they take a cue from manufacturers.

On their packaging, some manufacturers show these machines near a sleeping person, close to and facing a sofa, or on a desk near a keyboard. One manufacturer recommends putting its model near those suffering from breathing or other health problems.

If you own one of the five poor performing ionizers, CR suggests trying to return it for a refund.

However, not all air cleaners produce significant amounts of ozone. The top-performing Friedrich C-90A, an ionizing electrostatic precipitator model, is very effective and emits little ozone. Another fine performer that emits little ozone is the Whirlpool 45030, which is a HEPA-filter model.

How CR tested ionizing air cleaners for ozone levels: CR replicated the test used by manufacturers by using a sealed polyethylene room specified by Underwriters Laboratories Standard 867. Ozone levels were measured 2 inches from each machines air discharge in accordance with the standard. Because people dont live in sealed plastic rooms, CR also tested these ionizing air cleaners in an open well-ventilated lab. In this test, CR measured ozone levels 2 inches from the machines, as it did in the sealed room test, and 3 feet away, since ozone becomes diluted and dissipates rapidly indoors.

About the risks of indoor ozone: Ionizers now account for about 25 percent of the roughly $410 million per year spent on air cleaners. Experts agree that an ozone concentration of more than 80 ppb for eight hours or longer can cause coughing, wheezing, and chest pain while worsening asthma and deadening sense of smell.

A 14-year study of 95 urban areas in the U.S. found a clear link between small increases in ozone and higher death rates. The study, which appeared in the November 2004 Journal of the American Medical Association, predicts that a 10-ppb increase in ozone over eight hours could lead to roughly 3,700 premature deaths per year in some cities.

While ozone dissipates indoors, it can create other pollutants in the process.

Air cleaners need not meet ozone limits - not for the Environmental Protection Agency, which regulates only outdoor air, nor for the Food and Drug Administration, since it does not consider them medical devices. No federal agency sets indoor ozone limits for homes.

The Consumer Product Safety Commission is reviewing data on all air cleaners that create ozone and is evaluating whether the 50-ppb industry standard is adequate protection for consumers.

Recommendations: Consumers Union, the independent, nonprofit publisher of CR, believes that the Consumer Product Safety Commission should set indoor ozone limits for all air cleaners and mandate performance tests and labels disclosing the results. The Federal Trade Commission should take a close look at air-cleaner ads to determine whether they include unsubstantiated claims.

CR advises thinking twice about buying any air cleaner before following a few simple low- or no-cost cleaning methods, suggested by the Environmental Protection Agency and the American Lung Association, such as reducing indoor pollutants and keeping your home ventilated. If you buy an air cleaner, choose one that works from models CR recommends.

CR illustrates where ozone is produced inside ionizing air cleaners. CR also illustrates the inside of a HEPA air cleaner to demonstrate how many air cleaners operate.