The Wall Street Journal-20080129-Air Purifiers Draw Scrutiny- Some Devices Produce Ozone- Which Can Pose Health Risks- Agency Considers Safe Levels

Return to: The_Wall_Street_Journal-20080129

Air Purifiers Draw Scrutiny; Some Devices Produce Ozone, Which Can Pose Health Risks; Agency Considers Safe Levels

Full Text (1422  words)

Pressure is growing on makers of popular devices that promise to clean up indoor air -- but that can actually produce their own pollution.

People spend about 90% of their time indoors, breathing air that contains higher concentrations of many pollutants than outdoor air, according to the U.S. Environmental Protection Agency. Concern about the health impact of that air has given rise to a growing market for air cleaners, sold online and via popular retail outlets such as Sharper Image and Brookstone.

But some experts worry that many of these devices produce ozone -- a highly reactive gas that, while beneficial in the upper atmosphere as a filter of harmful UV rays, is a pollutant on the ground. Ozone is considered a toxic gas by the EPA, and its adverse effects include lung damage, exacerbated asthma symptoms and, at high levels of exposure, an increased risk of death.

Ozone-producing purifiers come in two categories. One is the "ozone generators," which release high amounts of the gas on purpose, claiming that ozone breaks down contaminants. These devices, such as Zontec Perfect Air 100 and Jenesco FM-1 air purifiers, can be purchased from a variety of Web sites. Second are the air cleaners more commonly known as "ionizers" or "electrostatic precipitators," which work by electrically charging airborne particles so they can be more easily collected and removed. These release small amounts of ozone as a byproduct. Popular machines include the Friedrich C-90B, the Kenmore K6 85264 and the Honeywell QuietClean.

Manufacturers of both types of air purifiers -- ozone and ionic -- say that the machines are safe when used properly, and that further research is needed to understand their impact. Kenneth Brumleve, owner of Jenesco, an Amherst, N.H., company that makes ozone purifiers, agrees that his machines produce high levels of the gas. But he says he warns customers that it's best to use the machines in areas when they are unoccupied "because ozone in high concentrations is not healthy to breathe."

Dean Gruber, president of Zontec Ozone Inc. in Tampa, Fla., which sells ozone generators, defends the machines' ability to get rid of strong smells. "The only other choice is to throw in a bunch of chemicals there, and what do you think is healthier?" he says.

Friedrich Air Conditioning Co., the manufacturer of the C-90B, notes that its electrostatic precipitator received top ratings in last month's Consumer Reports. A company spokeswoman said that its purifier does produce "small amounts of ozone," but that levels fall below voluntary government limits.

The U.S. Consumer Product Safety Commission, or CPSC, which has jurisdiction over residential air purifiers, hasn't set ozone limits for such devices.

Spokesman Scott Wolfson says the commission is now evaluating whether an ozone limit of 50 parts per billion -- a relatively low level that basically means 50 volumes of ozone per every billion volumes of air -- is safe for human health. The limit is already set by the Food and Drug Administration for Medical Devices.

And Underwriters Laboratories -- a testing organization that sets industry standards and provides a UL seal -- adopted more stringent testing standards to evaluate whether purifiers comply with the 50 ppb ozone limit. Testing standards and the 50 ppb limit are voluntary, but the CPSC says it could use them "as a platform" to take future action -- initiating a recall, or moving to make the standard mandatory, for example -- if there is noncompliance.

Many ion-generator companies voluntarily comply with the FDA's ozone limits of 50 ppb for their machines. Ozone-generator makers tend not to, though, acknowledging their machines wouldn't pass that standard. Ozone machines used at home generally produce levels of 250 to 500 parts per billion, according to the California Air Resources Board.

Because of their potential to produce high levels of the gas, ozone generators have been targeted by health authorities for some years now. Canada, Connecticut, Ohio and California have been warning consumers for the past several years against using the machines. But the devices "are still being sold on a regular basis and the public is still buying them," says Richard Shaughnessy, director of the University of Tulsa's Indoor Air Program.

Sales of portable home air purifiers were $310 million in 2005 -- the latest figures available -- with sales increasing 3.4% a year, according to Freedonia Group, a market-research firm in Cleveland.

California recently became the first state to pass a law regulating ozone emissions from all types of residential air purifiers. Starting in 2010, no machine intended for home use may produce an ozone concentration higher than 50 ppb.

A 2006 survey of about 2,000 people in California found that 2% of the state's households owned ozone machines and that more than 70% of owners kept them running continuously. The study, performed by the University of California Berkeley and funded by the state's Air Resources Board, estimated that more than 500,000 state residents were being "routinely exposed" to unhealthy levels of ozone via the devices.

In Canada, where it is estimated that between 14,000 to 28,000 ozone generators are sold every year, the government is working on legislation to limit ozone emissions from the machines, after finding sufficient evidence that the gas poses a direct hazard to health, according to Health Canada, the country's governmental health agency.

Ozone generators do have their merits, say many customers.

They are widely used in the hotel industry. "It makes an amazing difference," says Victor Martin, general manager of the Best Western Sterling Inn in Sterling Heights, Mich. The hotel says it operates the machines when rooms are being serviced and nobody is inside, and Mr. Martin says the ozone gets rid of smoke and other unpleasant odors.

The levels of ozone produced by these machines "can remove some odors but not all odors" and "are partially effective at killing microbes, but not fully effective," the California Air Resources Board said in a statement.

But another growing concern is that the chemical reactions caused by ozone could be leading to hazardous byproducts. A number of studies have shown that ozone can react with household chemicals and surfaces to produce harmful secondary chemicals.

One 2006 study in the journal Environmental Science and Technology found that upon three hours of exposure to ozone, surfaces such as carpet chemicals and cooking-oil residue on kitchen countertops reacted with ozone to produce formaldehyde, a suspected carcinogen, and other products.

Another 2005 study by researchers at the University of Texas found that when an ozone machine was turned on in the presence of a pine-oil cleaner, it produced "significant increases" in so-called ultrafine particles, a pollutant that is of concern to health experts because of the particles' ability to penetrate deeply into the lungs. The results "add evidence to the potentially harmful effects of ozone generation in residential environments," the study said.

Jeffrey Siegel, a researcher at the University of Texas at Austin, has found that these ozone reactions can occur from very low levels of the gas. "There are many scientists that still believe that even 50 ppb is a concentration that is of concern," adds Dr. Shaughnessy.

Dr. Siegel's studies have mainly focused on air ionizers. In one study, he tested several popular ion generators in the presence or absence of a household air freshener. When the freshener was present, he contends that the small amounts of ozone from the machines resulted in the creation of ultrafine particles.

"Every single one of the ion generators we tested was a net producer of particles, so they ended up generating more particles than they could remove," he says. Dr. Siegel declined to name the brands of ionizers in the test.

A spokeswoman for Friedrich Air Conditioning says that based on an initial assessment of work by Dr. Siegel, the company had "not seen conclusive evidence in support of these concerns."

Sharper Image Corp., the specialty retailer that is one of the largest marketers of air ionizers, declined a request for an interview, citing pending litigation. In a statement, the company said that its ionizers comply with the 50 ppb limit.

In a 2005 case that became a class action, a customer sued the company in U.S. District Court in Miami, alleging that its ionizers were ineffective and released dangerous amounts of ozone. A proposed settlement of the case was rejected by the court in October. (Drs. Shaughnessy and Siegel say their research with air purifiers is not funded by industry. They have both done work on behalf of plaintiffs in the continuing litigation against Sharper Image.)