Vol. 18 •Issue 9 • Page 25
Clearing the Air
Is Ozone Safe for Home Use?
It’s just a hunch, but Californians probably know a lot more than the rest of us about ozone (O3), that unstable, short-lived allotrope of oxygen with three atoms, as distinguished from the O2 we breathe in to live.
Los Angelinos, in particular, squint through their famously hazy layer of ozone (popularly called smog) that sits trapped in a bowl formed by the San Bernardino Mountains.
So it’s fitting that California’s Air Resources Board (ARB) is leading a public relations charge against the use of one particular type of air purifying system for the home: the ozone generator.
At least 12 manufacturers market ozone generators to eliminate bacteria and odors in the home, the ARB estimates. These devices generate ozone synthetically by means of bulbs that emit 157 or more nanometers of ultraviolet light. Commercial ozone generators are used in some poultry factories to combat the odor of chicken feces; hotels use them to eliminate cigarette/cigar smoke and other odors in just-vacated rooms.
Ozone generators for the home are about the size of small suitcases. Some can cost more than $500.
Far from removing odors, residential ozone generators “deaden the sense of smell, giving occupants a false sense of security because they cannot detect any indoor odors, including elevated ozone levels,” Dorothy Shimer, an ARB staff member, declared at an ARB board meeting in January.
What’s more, Shimer charged, ads for ozone generators are “often targeted at those people most susceptible to the ill effects of ozone: people such as the elderly and those with asthma, people who purchase these devices in hopes of improving their health.”
The ARB, the American Lung Association, the Environmental Protection Agency and his organization “all speak with one voice,” Mike Tringale, director of communications for the Asthma and Allergy Foundation of America, told ADVANCE. “There is no place for ozone generators in residential use.”
Tringale stressed that their wrath is directed toward true ozone generators, not other types of home air purifiers that produce ozone merely as a byproduct.
“People confuse ozone generators with fan-driven HEPA filters or negative and positive ion cleaners,” he said. “If something produces ozone intentionally and ozone is the mechanism of action that ‘cleans’ the air, it is an ozone generator. And most manufacturers proudly proclaim them as such.”
Manufacturers contacted by ADVANCE defended ozone as a natural purification process that can be safely harnessed and used.
“Ozone is an organic entity, created by nature and sunlight to kill standing bacteria. That’s the reason ozone is made,” said Ed Otero, president of Aqua Sun Ozone International, of Palm Springs, Calif., maker of the Kleenair 2500R, a residential air purifier that combines ionization with ozone generation and sells for $475. “And it’s only made for 20 minutes. It shoots off that extra atom and is gone.”
Ozone tends to be the fall guy when, in fact, the real villains are man-made pollutants like smokestack emissions and, especially, car exhaust, Otero said. “During high smog alerts, officials don’t say ‘Our hydrocarbon emissions are high today,'” he noted. “They say, ‘The ozone level is high today.’ Nature is creating that ozone to destroy or oxidize all the hydrocarbons automobiles are putting out that the wind is not destroying.”
According to his company’s Web site, the Kleenair 2500R produces negative ions, which “attach themselves to airborne particulates through a process known as ionization, which then make the particulates heavier than the surrounding air, causing them to drop and fall to the ground.”
At the same time, it generates ozone as a byproduct, which attaches to airborne pollutants and oxidizes them. “Together these two processes act in concert with one another in nature to clean and purify the air,” according to the Web site.
“Anytime you have an ion generator, you have a byproduct and that is ozone,” Otero explained. The Kleenair 2500R, he stressed, generates .01 parts per million (ppm) of ozone in an eight-hour period, far below the standard of .03 ppm considered safe by the U.S. Occupational Safety and Health Administration (OSHA).
Another manufacturer emphasized that ozone generation removes odors but has no curative powers over asthma and allergies.
“There definitely are circumstances where ozone should be and should not be used,” said Michael Waters, president of Comtech Research, of South Greenfield, Mo., maker of several types of air purifiers, mostly ion generators.
“For example, ozone is not a solution for airborne particulates like pollen, dust and other allergens. It is strictly indicated only for destroying certain unwanted odors like pet odors, normal household odors or fragrances.”
Ozone is very good for “quickly deodorizing areas where smokers have been, like a car or hotel room,” Waters continued.
“However, ozone levels required for that purpose are toxic, and no person or animal should be present in the area until the ozone levels come down to a safe concentration,” he added.
But, he added, many people who suffer from multiple chemical sensitivity and are allergic to fragrances “most certainly can and do benefit from the judicious use of ozone, because the O3 oxidizes many such compounds into simple H2O and CO2. Ozone does not mask the odors, as do some chemicals, fragrances or agents.”
Critics of ozone generators concede that their condemnation is not supported by much direct experimental evidence.
“There is not a whole lot of research that supports claims ozone generators are unhealthy,” Tringale said. “There is lots of research that particulate matter in outdoor air has a negative effect on respiration, particularly for those with compromised respiratory systems. But there’s no epidemiological evidence about the presence of indoor ozone and health. So a lot is inferred from the outdoor research.”
However, he added: “All the non-profit groups say, ‘Even though the evidence is not voluminous, we still suggest staying away from them.’ As a rule, ozone generators are frowned upon.”
There is some research to report. EPA officials tested four ozone generators in the den and bedroom of a “test house” and found they generated far more ozone than California’s ambient air quality standard of 90 ppb for one hour, Shimer testified before the ARB board. In fact, one generator in the den, when the central air conditioning was turned off, hit 310 ppb, more than three times the state standard and “equal to a Stage 1 Smog alert,” she said.
Ordinarily, home-size ozone generators don’t generate very much ozone, not like industrial-size machines used to reduce smoke damage after a fire in a building, allowed Gennet Paauwe, a spokesperson for California’s ARB.
Still, she is adamant about her message. “Ozone smells like fresh rain, like the smell of outdoor air just charged from lighting,” Paauwe said. “But over time, it deadens one’s sense of smell and possibly causes respiratory symptoms.”
While the ARB has purview over only outdoor air quality, neither it nor any other agency can regulate the quality of indoor air. “So we give out information only to alert the public,” she said.
“We’re trying to reduce ground-level ozone outdoors. Bringing ozone generators into the home exacerbates the problem given the enclosed area and the fact that they can be used improperly by homeowners,” she added.
Some irresponsible manufacturers are to blame for confusing homeowners about proper use of their products, Waters contended.
“There are several brands of ozone generators that are being incorrectly marketed as ionizers, or negative ion generators,” he said.
“Ozone is being used in areas where no gaseous odors are present and, as a result, ozone builds up to excessive levels even at some distance from the source of ozone,” he noted.
Furthermore, he said, “instructions that come with some heavily advertised and irresponsibly marketed products that generate ozone incorrectly indicate not only that ozone will destroy particulates and germs at safe levels but also that the machine should be left on, no matter what.
“As a result of leaving the generator on when there are no gases for the ozone to react with, harmful amounts of ozone can accumulate at such high levels that they can temporarily dull the sense of smell and even cause harm to mucous membranes and the respiratory system.
“The bottom line is if you can walk into an occupied building where ozone is being used—and you can smell ozone—then the ozone needs to be either turned down or turned off, period.”
Even common household electric products like hairdryers, toasters and microwave ovens release ozone as a byproduct, Tringale noted. So do the fans in HEPA filters.
“It’s a naturally occurring byproduct as opposed to a primary product of the device,” he said. “The crucial question is: at what level does that byproduct occur?”
HEPA filters and ion generators fall within the limit of .05 ppm of ozone, the specific standard for air cleaners in the code of federal regulations adopted from the Electronic Manufacturers code, Tringale said.
“Devices that emit ozone under .05 ppm are not considered ozone generators,” he said. “Exceed that threshold, and you have an ozone generator. We recommend not using a device that exceeds this threshold.”
Devices that don’t bear the Underwriter’s Laboratory (UL) seal, the standard international seal of safety for electronic products, “haven’t been tested, and they probably wouldn’t pass,” he added.
Many people, even those without asthma or allergies, are convinced that air-cleaning is a panacea, Tringale concluded.
“Air filtration may indeed be indicated medically, if the trigger source is an airborne allergen,” he said. “But we want to remind people that before they put even one dollar into air filtration, there are so many other things they should be doing, such as understanding what triggers their asthma and avoiding it.”
You can reach Michael Gibbons at firstname.lastname@example.org.