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Why You Shouldn’t Buy Ozone-Generating Air Purifiers

ozone gets trapped in your home

(Ozone released from ozone-generating air purifiers gets trapped in your home)

Air Purifiers That Help and Those That Don't

Indoor air pollution is a serious health hazard that needs to be addressed. For those concerned with reducing harmful pollutants in their homes, air purifiers, along with controlling the sources of pollution and ensuring adequate ventilation, can help keep these unhealthy chemicals and objects down to a minimum. However, not all indoor air purifiers are created equal. Some are more effective than others, and some, unfortunately can cause bigger air quality problems than they solve.

"Ozone is a toxic gas with vastly different chemical and toxicological properties from oxygen." -
United States Environment Protection Agency

Smart buyers will research the effectiveness of the various types of air purification systems available on the market. This article will focus on one specific problem that some kinds of "purifiers" produce: ozone. Some companies produce air cleaners that deliberately introduce significant quantities of ozone into your home. But ozone is an extremely unhealthy substance that can cause significant health problems for people who are exposed to it. If pumping a pollutant into the air to counteract pollutants sounds odd to you, you're right.

The purpose of this article is to explain why, if you are shopping for an effective, high-quality air cleaner, you should not purchase any air filter that generates ozone. First we will discuss ozone: what it is, and what effects the Environmental Protection Agency has found it can have on the human body.

What is Ozone?

Ozone is a molecule that is made up of three oxygen atoms. Therefore it is often abbreviated as O3, and you will occasionally hear it called "trioxygen." Many people will be familiar with the term "ozone" from hearing about the ozone layer that exists in the earth's stratosphere. Up there, some ten or more miles above the planet's surface, ozone is helpful to humans; it serves to block out harmful radiation emanating from the sun. In fact, without it, life as we know it would not be possible. One sometimes hears of ozone holes, where the ozone has been depleted and radiation enters the atmosphere in higher than normal levels.


(structure of an ozone molecule, 3 oxygen atoms and their charges - Image Source: Wikipedia)

Are Manufacturer Claims Legitimate?

The impression people receive is that ozone is a beneficial substance, and, as far as the ozone layer goes, that is certainly the case.  Manufactures of ozone-generating devices play on this perception, as well. They may also use enticing terms like "energized oxygen" to describe ozone as just another form of the oxygen we breathe. However, chemistry just doesn't work like that: to quote the EPA's report "Ozone Generators that Are Sold as Air Cleaners," ozone is "a toxic gas with vastly different chemical and toxicological properties from oxygen."

However, someone who is only informed about the role ozone plays in shielding us from radiation may think of ozone solely in terms of its benefits and not be aware of the dangerous results that close contact with it can have. It is possible to speak of "good" ozone and "bad ozone," but the only difference between the two is location. If you are breathing it, it is always the bad kind. In other words, when it comes to ozone, the EPA wants us to remember the slogan "good up high, bad nearby."

"At ground level, ozone is a harmful pollutant." - Environmental Protection Agency

Ozone is released by many pollution sources, such as car exhaust, chemical plants, and refineries, and is one of the substances monitored by the EPA under the Clean Air Act. The last thing you need is a so-called air purifier that pumps such a chemical directly into your home's air.

Next, we will briefly discuss what it is about ozone that makes it so bad for your health.

Why is Ground-Level Ozone Unhealthy?

As we said above, ozone consists of three oxygen atoms that have bonded together. Usually when we speak of "oxygen," we do not refer to a single oxygen atom but rather a molecule made up of two oxygen atoms, O2. It is this form of oxygen that humans and animals need to stay alive. This is because oxygen atoms naturally tend to bond with each other. A molecule consisting of two oxygen atoms is stable; the two atoms are tightly bound together and are not easily separated.

Ozone Bonds to Your Lungs

This is not the case with ozone. The third oxygen atom can become detached relatively easily, leaving instead one normal oxygen molecule with two atoms, and a single oxygen atom that is not bonded to anything else. It is this tendency to decay that makes ozone so dangerous.

Single oxygen atoms "want" to bond to something else, so to speak, and they will not only do so with one another. They can also attach themselves to organic compounds, such as those found in your body. When they do so, this completely changes the properties of whatever the oxygen atom has bonded with. The final result of the process for you, if you inhale ozone, is damage to the matter that makes up your body. This is why the EPA states that, however necessary ozone is in creating the conditions that allow life on Earth, "at ground level, ozone is a harmful pollutant."

In short, by breathing the air in an ozone-rich environment, you are ingesting a substance that will wreak havoc on your lungs. Now let us take a look at the specific problems that arise when you are exposed to ozone.

The Negative Health Effects of Ozone

Breathing in ozone can damage your lungs and have a number of ill consequences. The following list is based on the EPA's findings regarding the health effects of ozone exposure:

  1. Causes Coughing -  Ozone can make you cough, irritate your throat, leave you short of breath, and cause aching in your chest, even in relatively low doses.
  2. Inflames Your Lungs -  It can damage your respiratory system by inflaming the cells that line your lungs.
  3. Possible Permanent Lung Damage -  It can cause permanent damage to the lungs themselves in some instances. For example, if a child is exposed to ozone, it can interfere with the growth and development of the lungs. In adults, it can accelerate the deterioration of the lungs that comes naturally with aging.
  4. Worsens Asthma - If someone with asthma inhales ozone, it can worsen his or her condition even further.
  5. Worsens Emphysema and Bronchitis - Likewise, ozone can exacerbate other lung diseases as well, including emphysema and bronchitis.
  6. Interferes With Immune System -  It can interfere with the functioning of the body's immune system around the lungs, leaving you more vulnerable to airborne infections because your body is less capable of fighting them off.
  7. Damage Continues - Some of the immediate irritation caused by ozone may subside after a few days of exposure, even if you are still inhaling it at the same levels. Though this might feel like a relief, it can lull us into a false sense of security. The EPA pamphlet "Ozone and Your Health" (PDF) states that "ozone continues to cause lung damage even when the symptoms have disappeared."

As you can see, it would be wise to take care to avoid ozone whenever possible. But if ozone is so unhealthy, why do some air purification manufacturers make products that deliberately introduce it into your home? We will now move from discussing ozone in general to examining the effectiveness and safety of these systems.

Ozone-Generating Air Purifiers: Do They Work?

The idea behind air cleaners that produce ozone is based on ozone's reactive properties. As we said earlier, ozone is highly unstable and will break apart, leading to further chemical reactions. Makers of ozone generators suggest that this process will destroy many of the unhealthy airborne chemicals in your home. But the EPA, which has done considerable investigating into the effectiveness of ozone generators, disagrees, and lists three problems with these claims.

Ozone Air Purifiers Are Largely Ineffective

  1. Many pollutants are not damaged by ozone - The EPA goes so far as to say in "Ozone Generators that Are Sold as Air Cleaners" that "for all practical purposes, ozone does not react at all with such chemicals." Ozone may quickly damage you, but that does not mean everything is equally vulnerable to it.
  2. Creation of new pollutants - When it comes to those things that ozone does neutralize, the reaction that destroys the original pollutant sometimes just creates new pollutants, leaving the air hardly any cleaner than it was before. One report prepared by the EPA suggests, for example, that "ozone is also believed to react with acrolein, one of the many odorous and irritating chemicals found in secondhand tobacco smoke."
  3. Ineffective Particle Removal - Ozone does not do anything about unhealthy particles in the air that comprise a good deal of the total amount of indoor air pollution. This would include pet dander or dust, for example. Traditional air filters are usually most effective at getting rid of particulate pollution, which means that if someone buys an ozone generator instead, he or she is missing the opportunity to do something significant to reduce pollution.

Beyond these points, further studies cited by the EPA have also indicated that ozone generators do nothing against many odor-causing substances commonly found in the home. One report, published in the official journal of the American Society of Heating, Refrigerating, and Air Conditioning Engineers, found that "body odor may be masked by the smell of ozone but is not removed by ozone."

Also, although there does exist some evidence indicating that ozone can be used to combat viruses and living pollution sources such as bacteria and mold, for this to have any measureable impact, the ozone would need to be present in qualities far above what humans can safely tolerate.

To sum it all up, ozone generators just don't work. That alone is enough reason to avoid buying them, of course. But on top of that, there is the question of safety, and on these grounds, as well, ozone generators fail.

Ozone-Generating Air Purifiers: Are They Safe?

In fairness, different kinds of ozone generators produce different amounts of ozone. Some, if used exactly as recommended by the manufacturer, may not create enough ozone to cause any damage. For all the reasons discussed in the previous section, these purifiers are still useless as a means of cleaning the air, but at least they aren't directly contributing to the problem they are advertised as solving.

Unfortunately, the EPA has found that, with some other brands of ozone-generating devices, "concentrations of ozone considerably higher than [recognized public health standards] are possible even when a user follows the manufacturer’s operating instructions" to the best of his or her ability. There are simply too many factors that can spring up and cause an increase in ozone exposure. The size of the room, whether doors or left open or closed, and the exact makeup of the air around the ozone generator all affect how concentrated the ozone will become.

Also, it is very difficult to take into account other sources of ozone (cars, factories, etc.) that may be nearby. It is possible that an ozone generator will not on its own produce enough ozone to be harmful, but when combined with these other sources, the amount of ozone crosses the danger threshold.

In conclusion, even if ozone generators did work as they are intended to do, and as they are marketed as doing, they just are not safe enough to put in your home.

What Are the Alternatives to Ozone Air Purifiers?

All the evidence indicates that ozone generators are neither effective nor safe. Therefore, first of all, if there are any ozone-generating devices in your house, turn them off at once. They are at best doing no good, and at worst they are adding to the pollution that you purchased them to reduce.

If you are concerned about indoor air quality, the good news is that there are plenty of air purification systems available for houses and apartments that do not produce any ozone at all. There are much better and safer methods of eliminating toxins from the air, and the EPA acknowledges that some other kinds of air purifiers have a role to play in cleaning up the air you breathe at home.

Mechanical Air Purifiers The Best Choice

"Mechanical" air purifiers are those that use filters to capture particles that would otherwise float in the air, possibly to be inhaled by humans. These are likely to be the smartest choice, but be aware that they will not help against gaseous pollutants, only solid ones, especially smaller particles that remain in the air for an extended period of time. Even with a good air purifier, controlling the sources of pollution and making sure your home is well-ventilated are necessary steps.

Note that there are also electronic air purifiers, such as ionizers. However, these are not recommended because they, too, produce ozone, whether they were intended to do so or not. To take the most famous example, the makers of the well-known Ionic Breeze brand of purifiers eventually went bankrupt due to reports that their product produced high levels of ozone. Therefore, mechanical filters will be the best option for most people.

Summary and Conclusion

Ozone, a molecule consisting of three oxygen atoms, may help preserve life on earth when it is up in the stratosphere, but it also poses health risks for people when they inhale it. Although some companies sell "air purifiers" that supposedly fight toxic chemicals in the air with ozone, the truth is that these devices are ineffectual and sometimes downright dangerous. They can contribute to lung diseases, worsen pre-existing problems, and damage lung tissue. With so many potential health hazards floating around in your home's air, the last thing you need is add ozone into the mix.

Therefore, such devices should be avoided in favor of air filtration systems that do not produce ozone. A high-quality air purifier, operating on sound scientific principles, is an important weapon in the fight against indoor air pollution. And happily, there are good, effective air purifiers readily available to keep your home's air breathable.

Bottom Line - Before you purchase an air purifier, make sure that it does not produce ozone!


List of California Approved Air Purifiers
(No Ozone Generated During Operation)

Brand Model Name (Model Numbers) Type Date Notified EO
  Filtrete™ Ultra Quiet Room Air Purifier
Mechanical 02-26-2009 G-09-004
  Filtrete™ Ultra Clean Room Air Purifier
(FAP-02, FAP02-RC, FAP02-RS, FAP02-RY, FAP-03, FAP03-RC, FAP03-RS, FAP03-RY)
Mechanical 02-26-2009 G-09-004
  Filtrete™ Ultra Quiet Room Air Purifier
Other* 12-02-2009 G-09-118
Aerus (Blueair AB)
  Guardian Air Other* 05-12-2010  
Air King®
  42" Wind Curve
Other* 11-12-2009 G-09-102
  48" Tower Fan
(9820, 9820A)
Other* 11-12-2009 G-09-102
Atmosphere (Access Business Group)
  Atmosphere™ Air Purifier
Mechanical 04-27-2009 G-09-014
Blueair AB
(403, 450E, 503, 550E, 603, 650E)
Other* 05-12-2010  
(203, 270E)
Other* 07-09-2010  
Electrolux (Winix)
  EL500A Mechanical Pending**  
Other* Pending**  
Febreze®/True Air (Hamilton Beach)
  Direct Plug-In Odor Eliminator
(04530C, 04530F, 04531C, 04531F)
Mechanical 12-17-2009 G-09-103 
GE (Woongjin Coway)
  Small Air Purifier
Mechanical 05-04-2009 G-09-015
  Large Air Purifier
Mechanical 05-04-2009 G-09-015
  Super Air Purifier
Mechanical Pending**  
Holmes (Jarden Consumer Solutions)
Mechanical 03-16-2010  
Honeywell® by Kaz®
  enviracaire® Programmable True HEPA Air Purifier
(50310, 50311)
Mechanical 03-20-2009 G-09-006
  enviracaire® True HEPA Air Purifier
(50100, 50101, 50150, 50200, 50250, 50251, 50300, 50300-CST)
Mechanical 03-20-2009 G-09-006
  enviracaire® QuietClean
(60001 )
Other* Pending**  
  HEPA-Type Tabletop Air Purifier
Other* Pending**  
  HEPAClean Compact Tower
Mechanical 06-01-2010  
  HEPAClean Tower
Mechanical 06-01-2010  
  HEPAClean Air Purifier Dual Pack
Mechanical 06-01-2010  
  HEPAClean Tabletop Air Purifier
Other* Pending**  
  HEPAClean Tower Air Purifier
(HHT-080, HHT-081)
Other* 07-28-2009 G-09-006
  HEPAClean Tower Air Purifier
Other* 03-23-2010 G-10-014
  HEPAClean UV Tower Air Purifier
(HHT-145, HHT-149,
Other* 07-28-2009 G-09-006
  HEPAClean UV Tower Air Purifier
Other* 03-23-2010 G-10-014
  Pet Clean Air Air Purifier
(HHT-013, HHT-016-MP)
Mechanical Pending**  
  QuietCare™ True HEPA Air Purifier  
(17007, 17007-HD)
Mechanical 01-27-2010  
  QuietCare™ True HEPA Air Purifier  
(17200, 17205, 17205-CST)
Other* 01-27-2010  G-10-014
  QuietCare™ True HEPA Air Purifier with permanent filter
(17000, 17000-19, 17000-S, 17000BB, 17005, 17006, 17000N-KOL)
Mechanical 03-20-2009 G-09-006
  QuietCare™ True HEPA Air Purifier with permanent filter
Mechanical 08-12-2009 G-09-006
  QuietClean Air Purifier
(HFD-015, HFD-1101, HFD-110, HFD-112, HFD-116C )
Other* 06-30-2009 G-09-006
  QuietClean Air Purifier
(HFD-135, HFD-137, HFD-139)
Other* Pending**  
  QuietClean Air Purifier with permanent filter
(HFD-120-Q, HFD-120-Q-1)
Other* 05-29-2009 G-09-006
  QuietClean Air Purifier with permanent filter
(HFD-122C, HFD-015C)
Other* 10-19-2009 G-09-101
  QuietClean Antibacterial Air Purifier
Other* Pending**  
  QuietClean Compact Tower Air Purifier
Other* Pending**  
  QuietClean Tower Air Purifier
Other* 03-04-2010 G-10-014
  QuietClean Tower Air Purifier
Other* 03-23-2010 G-10-014
  QuietClean UV Tower Air Purifier
(HHT-215, HHT-217, HHT-219)
Other* Pending**  
  SilentComfort™ True HEPA Air Purifier
(18155, 18150)
Mechanical 03-20-2009 G-09-006
  True HEPA Air Purifier
Mechanical 03-23-2010 G-10-014
  True HEPA Air Purifier with permanent filer
(50150-S, 50250-S)
Mechanical 10-19-2009 G-09-101
  True HEPA Compact Tower
Mechanical 06-02-2010  
  True HEPA Tower
Mechanical 06-02-2010  
Hunter Fan
  HEPAtech Air Purifier System
(30054, 30055, 37055)
Mechanical 06-30-2009 G-09-005
(30057,30059, 30710, 30711, 30730, 30748, 30750)
Other* Pending**  
  Permatype Air Purifier 
(30835, 30836, 30837)
Mechanical Pending**  
  Programmable HEPA Air Purifier
Mechanical 06-30-2009 G-09-005
  QuietFlo® HEPA Air Purifier
Mechanical 06-30-2009 G-09-005
  QuietFlo® HEPA Air Purifier
Mechanical 03-16-2009 G-09-005
  QuietFlo® Plus Air Purifier
(30785, 30780 to 30789)
Mechanical 06-30-2009 G-09-005
  QuietFlo® True HEPA Air Purifier
(30090, 30095)
Mechanical 03-16-2009 G-09-005
(30030 to 30039, 30040 to 30049, 37030 to 37039 )
Mechanical 06-30-2009 G-09-005
IDYLIS (Woongjin Coway)
  Air Purifier
(IAP-10-100, IAP-10-100C, IAP-10-125, IAP-10-125C, IAP-10-150, IAP-10-150C, IAP-10-200, IAP-10-200C, IAP-10-280, IAP-10-280C)
Mechanical Pending**  
  Cleanroom H13™
Mechanical 04-15-2010  
  Dental Hg™
(1D0 UA0 IGU, 1DA UA0 IGU)
Mechanical 04-15-2010  
  Dental Pro™
(1D0 UA0 IGU, 1DB UA0 IGU)
Mechanical 04-15-2010  
  GC™ AM
(1C0 UB0 HGU, 1CA UB0 HGB)
Mechanical 04-15-2010  
  GC™ ChemiSorber
(1C0 UB0 HGU, 1CB UB0 HGB)
Mechanical 04-15-2010  
  GC™ MultiGas
(1C0 UB0 HGU, 1CC UB0 HGB)
Mechanical 04-15-2010  
(1C0 UB0 HGU, 1CD UB0 HGB)
Mechanical 04-15-2010  
(1F0 UB0 LGU, 1FA UB0 LGB)
Mechanical 04-15-2010  
  GCX™ ChemiSorber
(1F0 UB0 LGU, 1FB UB0 LGB)
Mechanical 04-15-2010  
  GCX™ MultiGas
(1F0 UB0 LGU, 1FC UB0 LGB)
Mechanical 04-15-2010  
(1F0 UB0 LGU, 1FD UB0 LGB) 
Mechanical 04-15-2010  
Mechanical 04-15-2010  
  HealthPro® Compact
Mechanical 04-15-2010  
  HealthPro® Compact Plus
Mechanical 04-15-2010  
  HealthPro® Plus
Mechanical 04-15-2010  
Lasko Products®
  42" Wind Curve™  
(2551, 2554)
Other* 11-12-2009 G-09-102
  48" Tower Fan
(4820, 4822)
Other* 11-12-2009 G-09-102
  Cyclonic Ceramic Heater
(5840, 760000, 6000)
Other* Pending**  
  Compact Tower Air Purifier
Other* Pending**  
  QuietClean Air Purifier
Other* 06-30-2009 G-09-006
  Professional Air Purifier
Other* 04-22-2010 G-10-038
  ProShield Air Purifier
Other* 03-10-2010 G-10-038
Rexair, LLC
(E2 Type 12)
Mechanical 02-01-2010 G-10-015
  RainMate Air Freshener
Mechanical 02-01-2010 G-10-015
  Air Purifier
(FP-P30U, KC-830U)
Other* 03-23-2010 G-10-036
  Air Purifier
Other* 06-23-2010  
  Portable Air Conditioner
Other* Pending**  
SwissAir™ (IQAir North America)
  SolventMaster JV3
(1S0 UB0 000 / 1S0 UB0 PGT)
Mechanical 04-15-2010  
True Air® (Hamilton Beach)
  Air Decor Air Purifier
Mechanical 01-06-2010 G-09-103
  Direct Plug-In Odor Eliminator
(04530, 04531)
Mechanical 12-17-2009 G-09-103
  Direct Plug-In Odor Eliminator
Mechanical 04-23-2010  
  Direct Plug-In Odor Eliminator
(04530GM, 04531GM)
Mechanical 06-07-2010  
  EcoClean Air Purifier
Other* 07-29-2010  
  Pet Air Purifier
Other* 07-29-2010  
  Room Size Odor Eliminator
Mechanical 11-23-2009 G-09-103
  Room Size Odor Eliminator
Mechanical 04-23-2010  
  Tower Allergen Reducer
Mechanical 04-23-2010  
  Tower Allergen Reducer
Mechanical 11-23-2009 G-09-103
UTLT+ (CCL Products Limited)
  Electrostatic Air Cleaner
Other* 03-03-2010 G-10-037
Vicks (Kaz)
Other* Pending**  

(Source: State of California, list approved December 2009 - #)

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