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Ozone Generators Create Home Smog

Air Purifiers That Produce Ozone May Be Hurting Your Health
By
WebMD Health News
Reviewed by Louise Chang, MD

May 11, 2006 -- You can create dangerous smog levels in your own home with an ozone-generating air purifier.

The finding comes from a study of ozone-emitting air purifiers by Sergey A. Nizkorodov, PhD, and colleagues at the University of California, Irvine. The researchers studied 13 air purifiers known to give off small and large amounts of ozone, a major ingredient in air pollution.

Included in the study were several ionic air purifiers made by The Sharper Image, including the popular Ionic Breeze Quadra. These machines produce detectable levels of ozone. But they did not emit dangerous levels of ozone, except when a Quadra model intended for a large room was tested in a tiny bathroom.

Ozone generators, however, were a different story. As they are designed to do, they put a lot of ozone into indoor spaces. The devices quickly caused ozone buildups to levels that would trigger severe smog alerts for outdoor air.

"If I put one in my office, I can generate a stage 2 ozone level if I want to," Nizkorodov tells WebMD. "This is the problem -- right now it is not controlled. Air purifiers that make ozone above a certain rate should be banned. The public should not be allowed to buy them."

Ozone is great in the upper atmosphere, where it protects the Earth from harmful radiation. Ground-level ozone, however, isn't our friend. According to the American Lung Association, ozone exposure may lead to premature death, shortness of breath, chest pain when inhaling deeply, and wheezing and coughing. High ozone levels irritate the lung and make asthma worse.

The Nizkorodov study, funded by the National Science Foundation, appears in the May issue of the Journal of the Air & Waste Management Association.

Ozone Generators vs. Ionic Air Purifiers

It's easy for consumers to be confused. Three basic kinds of devices call themselves air purifiers. None is foolproof. Consumer Reports has found that "even the best air cleaners could be a frivolous investment."

There's no ozone emission from air purifiers that use only high-efficiency particulate air filters (HEPA filters) to cleanse the air. Ionizing air purifiers, because of their electric charge, do create ozone. Consumer Reports has warned that they may give off potentially harmful ozone levels.

"There are plenty of ionic air purifiers; only a small fraction make ozone," Nizkorodov says.

Mark Connelly, senior director of appliances and home improvement for Consumer Reports, oversees the magazine's air-cleaner tests.

"You don't want to say that anything that generates ozone is bad," Connelly tells WebMD. "A printer produces ozone, but just because printers sit on people's desks doesn't mean they should be taken off the market. But the people who buy air purifiers are most susceptible to the problems they create. You buy it to make things better, and it ends up making things worse for you."

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