Do commercial ozone generators work?

Reviewed by Dr. Yogi Goswami PhD, Co-founder and Chief Scientist

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Advertising can be powerful. You may have heard manufacturers describe ozone generators as &#;natural odor removers&#; that work &#;the way nature intended.&#; But are these claims misleading? Find out more about ozone air purifiers in this article to help you decide what is best for you and your family.

What is ozone?

As you may know, ozone is a gas. Ozone molecules have three oxygen atoms (O3), unlike the oxygen in the air that gives life to the planet (O2). Ozone is powerful because the extra oxygen atom can easily escape and attach to other substances. This highly reactive quality can potentially alter the chemical composition of some substances in the air and affect our cells if we breathe it in.

When you hear the term &#;ozone&#; you may think of the ozone layer, which protects all life from the dangerous UV radiation of the sun. This is the &#;good&#; ozone that is present in the stratosphere. But the ozone at ground level is &#;bad&#; since it is hazardous to health and is classified as an air pollutant by the EPA. Ozone at the ground level is created in nature by the interaction of sunlight with certain chemicals that are released to the environment, including vehicle and industrial plant emissions. It is also created when lightning strikes, which is why you may be able to smell ozone after a storm. Ozone, whether pure or mixed with other chemicals, can be harmful to health.

Is ozone bad for you?

Yes, whether ozone is mixed with other chemicals or in pure form, it can be harmful to your respiratory system when inhaled.

Since the early 20th century, health professionals have warned about the dangers of ozone. Just as it reacts with substances outside of the body, it can react with the living tissue within your body. This means that ozone can cause a variety of health problems, like coughing and airway inflammation. It can also reduce lung function and harm lung tissue. Certain groups like children, people with asthma, and older adults are especially vulnerable.

You may have heard of the Clean Air Act. Under this federal law, the Environmental Protection Agency (EPA) sets standards for outdoor air quality to protect public health. There are six air pollutants that the agency has set standards for, and ozone is one of them. If ozone is dangerous enough for the EPA to monitor outdoor levels, then it is all the more dangerous for ozone generators to release pure ozone into your home.

For context, the US Food & Drug Administration (FDA) requires that indoor medical devices can only produce a maximum of 50 ppb (parts per billion) of ozone. The National Institute of Occupational Safety and Health (NIOSH) recommends that indoor ozone levels should not be greater than 100 ppb.

What are ozone generators?

Ozone generators, also referred to as ozone machines, are ozone-generating devices that intentionally produce ozone gas. When sold as air purifiers to be used in indoor occupied spaces, they are marketed to be safe and effective (though these claims are generally false). This article discusses devices that produce ozone on purpose and not as a byproduct. Ionizers and electrostatic precipitators end up producing ozone as a byproduct as a result of their internal mechanisms.

You may have heard about ionizers. They used to be quite popular and were often used in homes to clean the air and eliminate odors. However, in the spring of , Consumer Reports Magazine exposed the units as potentially doing more harm than good&#;it was found that several of these devices could produce harmful levels of ozone. Though ozone is a byproduct of these ionizers, and tends to be produced at a lower level than ozone generators, the federal government began a stricter regulation process for any air purifier that produces ozone, whether intentionally or as a byproduct.

No federal agency has approved the use of ozone generators in occupied spaces, and the California Air Resources Board (CARB) has very strict regulation for air purifiers sold in California to make sure that harmful ozone levels are not being produced.

How do ozone generators work?

Ozone generators produce ozone by breaking apart oxygen (O2) molecules into single atoms, which then attach to other oxygen molecules in the air to form ozone (O3). They accomplish this in one of two ways, according to the International Association of Certified Indoor Air Consultants (InterNACHI).

Ozone generators work by:

• Silent corona discharge: These machines use electric discharge to produce ozone by splitting the normal oxygen molecules in the air into single atoms. These atoms then attach to other O2 molecules in the air to form ozone (O3).
• Ultraviolet radiation: This process of ozone generation is similar to how the sun&#;s ultraviolet radiation splits O2 to form individual oxygen atoms. According to InterNACHI, this process is considered to be less efficient than corona discharge.

Why are ozone generators used to purify the air?

If ozone is so dangerous, then why would anyone use it to purify the air inside a home? As discussed above, ozone is highly reactive and can change the chemical composition of some substances in the air. This principle forms the basis of manufacturers&#; claims.

Companies who sell ozone generators may suggest that ozone is a healthy kind of oxygen, using terms like &#;activated oxygen&#; or &#;pure air,&#; though ozone is actually a toxic gas that is not the &#;same as air&#; like manufacturers may claim. Ozone-generating devices are often marketed as odor removers. Ultimately, they are used to remove organic compounds from the air. However, given its danger to health, it would be wise to use an ozone generator only if there are clear benefits.

How effective are ozone generators?

Manufacturers&#; claims

Manufacturers say that the highly reactive nature of ozone allows it to easily attach to pollution, especially odorous compounds like smoke and organic matter such as viruses, bacteria and mold spores. However, these claims are not backed up by sound science.

Performance against mold and bacteria

Research has found that ozone generators were not effective at stopping mold or bacteria growth in a standard hospital room, and would require unsafe levels of ozone to do the job at all (Dyas, Boughton, & Das, ). For mold growth, public health departments do not recommend using ozone generators for clean-up, saying that ozone even at high levels cannot control mold.

Performance against VOCs

You may be asking yourself, if ozone gas is effective at anything, it should work on other gaseous pollutants (specifically volatile organic compounds, or VOCs) right? Well, it might not, unless you wait for thousands of years in some cases. A research study (Boeniger, ) analyzed how long it would take to remove 14 of the most common organic compounds found in the air. It was found that at ozone concentrations of 100 ppb, it would take 880+ years for six of these pollutants to be broken down into half of their initial concentrations (half-lives). In fact, it would take more than 4,400 years for formaldehyde! Only one pollutant, styrene, was found to have a half-life of about 4 hours.

Performance against particulates

You must remember that ozone generators do not remove particulate matter like dust or pollen (which are often allergens) from the air.

The EPA&#;s conclusion about effectiveness

The EPA concludes from a review of scientific research that at concentrations that meet public health standards, ozone is not very effective at removing indoor air contaminants.

Can ozone generators remove odors?

 

 

The million dollar question for you might be whether ozone generators can remove odors from the air. That at least is what manufacturers claim to be the most common use for ozone generators in homes.

However, the evidence is mixed as to whether ozone generators can remove most odors from the air. As mentioned above, ozone generators may not work efficiently at all for gases, namely volatile organic compounds (VOCs), as it could take hundreds of years for this process.

Yet, some research reviewed by Britigan, Alshawa, and Nizkorodov () has shown that ozone may be effective for certain types of VOCs (namely, those containing unsaturated carbon-carbon bonds). These types of VOCs are found in cooking oils, air fresheners, cleaning agents, etc. However, there is a big downside: other dangerous byproducts like formaldehyde can be released into the air when ozone reacts with these substances.

Here is another important point: What you might perceive as odor removal may just be facade. Odors in a room could be masked by the smell of ozone being released into the air. Many people who use ozone generators like the smell that is produced, describing it as a &#;clean sheet smell&#; or the smell of clothes fresh from the dryer (EPA, ).

What are the safety precautions of ozone generators?

Ultimately, you need to know that no agency of the federal government has approved using ozone generators in occupied spaces. If you must use one or have no choice in a certain situation, you should take every measure possible to make sure they are never used when people or animals are present in the room. Plants also should be kept outside of the area.

Many times, if ozone generators are used, they are used for commercial cleaning in hotels, cars, etc. Many hotels use them inside a room just before new guests arrive, which can be harmful because of any residual ozone that lingers in the air. Manufacturers of ozone generators recommend they only be used by trained professionals for odor removal, and that all other steps, like cleaning the area and removing any sources of the odor, should be done first.

What are some better solutions?

There are other solutions that are much safer and more effective than using any device that may cause an accumulation of ozone. The initial recommended steps are also the lowest-cost solutions to improving air quality. First of all, you should always try to remove the sources of odors or pollutants as much as possible. Second, you should try ventilating the area to allow for better air circulation in your home, if possible. You may want to disregard this step if you live near a source of high-level outdoor pollution or outdoor air quality is poor.

Afterward, using an air purifier that is not an ozone generator could be a good option to try. There are different types of air purifiers out there, from mechanical filters (like HEPA) that only remove particles from the air, or gas-phase filters like carbon filters that are only designed to remove VOCs. If you would like a more complete solution for cleaning the air, you might consider the Molekule technology, which is highly effective against mold, VOCs, allergens like pollen, bacteria, and viruses. It also destroys VOCs and biological contaminants, unlike the traditional air purifiers like HEPA that simply trap particles.

Additionally, if you are especially concerned about odors, there are other, much safer ways to make your room smell fresh.

Conclusion

Additional reading:
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Contact us to discuss your requirements of 800g Ozone Generator supplier. Our experienced sales team can help you identify the options that best suit your needs.

The negative aspects of ozone generators definitely outweigh any potential positive benefits, and it is best if you consider safer and more effective solutions for improving your indoor air quality, such as an ozone-free air purifier. Manufacturers of ozone generators often make false claims about their devices and say they are effective at odor removal. Overall, these devices are strictly regulated by federal law and the EPA and other federal agencies like the Air Resources Board (ARB) warn about their health dangers.

In general, there is no scientific evidence that ozone generators are effective, unless they produce extremely high levels of ozone. Ultimately, there are much more efficient, safer solutions to air quality problems. You can provide a safe space with clean, fresh air for you and your family through other methods including source control, ventilation, and using other air purifier options.

On this page:

There is a large body of written material on ozone and the use of ozone indoors. However, much of this material makes claims or draws conclusions without substantiation and sound science. In developing Ozone Generators that are Sold as Air Cleaners, the EPA reviewed a wide assortment of this literature, including information provided by a leading manufacturer of ozone generating devices. In keeping with EPA's policy of insuring that the information it provides is based on sound science, only peer reviewed, scientifically supported findings and conclusions were relied upon in developing this document.

Several brands of ozone generators have EPA establishment number on their packaging. This number helps EPA identify the specific facility that produces the product. The display of this number does not imply EPA endorsement or suggest in any way that EPA has found the product to be either safe or effective.

Please Note: EPA does not certify air cleaning devices. The Agency does not recommend air cleaning devices or manufacturers. If you need information on specific devices or manufacturers, one resource you can consult is the Association of Home Appliance Manufacturers (AHAM), (202) 872-. AHAM conducts four certification programs for each category - room air cleaners, room air conditioners, dehumidifiers and refrigerator/freezers. The air cleaner certification program is known as AC-1.

Introduction and Purpose

Ozone generators that are sold as air cleaners intentionally produce the gas ozone. Often the vendors of ozone generators make statements and distribute material that lead the public to believe that these devices are always safe and effective in controlling indoor air pollution. For almost a century, health professionals have refuted these claims (Sawyer, et. al ; Salls, ; Boeniger, ; American Lung Association, ; Al-Ahmady, ). The purpose of this document is to provide accurate information regarding the use of ozone-generating devices in indoor occupied spaces. This information is based on the most credible scientific evidence currently available.

Some vendors suggest that these devices have been approved by the federal government for use in occupied spaces. To the contrary, NO agency of the federal government has approved these devices for use in occupied spaces. Because of these claims, and because ozone can cause health problems at high concentrations, several federal government agencies have worked in consultation with the U.S. Environmental Protection Agency to produce this public information document.

What is Ozone?

Ozone is a molecule composed of three atoms of oxygen. Two atoms of oxygen form the basic oxygen molecule--the oxygen we breathe that is essential to life. The third oxygen atom can detach from the ozone molecule, and re-attach to molecules of other substances, thereby altering their chemical composition. It is this ability to react with other substances that forms the basis of manufacturers&#; claims.

How is Ozone Harmful?

The same chemical properties that allow high concentrations of ozone to react with organic material outside the body give it the ability to react with similar organic material that makes up the body, and potentially cause harmful health consequences. When inhaled, ozone can damage the lungs. Relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. Ozone may also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections. People vary widely in their susceptibility to ozone. Healthy people, as well as those with respiratory difficulty, can experience breathing problems when exposed to ozone. Exercise during exposure to ozone causes a greater amount of ozone to be inhaled, and increases the risk of harmful respiratory effects. Recovery from the harmful effects can occur following short-term exposure to low levels of ozone, but health effects may become more damaging and recovery less certain at higher levels or from longer exposures (US EPA, a, b).

Manufacturers and vendors of ozone devices often use misleading terms to describe ozone. Terms such as "energized oxygen" or "pure air" suggest that ozone is a healthy kind of oxygen. Ozone is a toxic gas with vastly different chemical and toxicological properties from oxygen. Several federal agencies have established health standards or recommendations to limit human exposure to ozone. These exposure limits are summarized in Table 1.

Table 1. Ozone Heath Effects and Standards

Health Effects Risk Factors Health Standards* Potential risk of experiencing:

Decreases in lung function

Aggravation of asthma

Throat irritation and cough

Chest pain and shortness of breath

Inflammation of lung tissue

Higher susceptibility to respiratory infection Factors expected to increase risk and severity of health effects are:

Increase in ozone air concentration

Greater duration of exposure for some health effects

Activities that raise the breathing rate (e.g., exercise)

Certain pre-existing lung diseases (e.g., asthma)

The Food and Drug Administration (FDA) requires ozone output of indoor medical devices to be no more than 0.05 ppm.

The Occupational Safety and Health Administration (OSHA) requires that workers not be exposed to an average concentration of more than 0.10 ppm for 8 hours.

The National Institute of Occupational Safety and Health (NIOSH) recommends an upper limit of 0.10 ppm, not to be exceeded at any time.

EPA&#;s National Ambient Air Quality Standard for ozone is a maximum 8 hour average outdoor concentration of 0.08 ppm

• See - the Clean Air Act

(* ppm = parts per million)

Is There Such a Thing as "Good Ozone" and "Bad Ozone"?

The phrase "good up high - bad nearby" has been used by the U.S. Environmental Protection Agency (EPA) to make the distinction between ozone in the upper and lower atmosphere. Ozone in the upper atmosphere--referred to as "stratospheric ozone"--helps filter out damaging ultraviolet radiation from the sun. Though ozone in the stratosphere is protective, ozone in the atmosphere - which is the air we breathe - can be harmful to the respiratory system. Harmful levels of ozone can be produced by the interaction of sunlight with certain chemicals emitted to the environment (e.g., automobile emissions and chemical emissions of industrial plants). These harmful concentrations of ozone in the atmosphere are often accompanied by high concentrations of other pollutants, including nitrogen dioxide, fine particles and hydrocarbons. Whether pure or mixed with other chemicals, ozone can be harmful to health.

Are Ozone Generators Effective in Controlling Indoor Air Pollution?

Available scientific evidence shows that at concentrations that do not exceed public health standards, ozone has little potential to remove indoor air contaminants.

Some manufacturers or vendors suggest that ozone will render almost every chemical contaminant harmless by producing a chemical reaction whose only by-products are carbon dioxide, oxygen and water. This is misleading.

• First, a review of scientific research shows that, for many of the chemicals commonly found in indoor environments, the reaction process with ozone may take months or years (Boeniger, ). For all practical purposes, ozone does not react at all with such chemicals. And contrary to specific claims by some vendors, ozone generators are not effective in removing carbon monoxide (Salls, ; Shaughnessy et al., ) or formaldehyde (Esswein and Boeniger, ).
• Second, for many of the chemicals with which ozone does readily react, the reaction can form a variety of harmful or irritating by-products (Weschler et al., a, b, ; Zhang and Lioy, ). For example, in a laboratory experiment that mixed ozone with chemicals from new carpet, ozone reduced many of these chemicals, including those which can produce new carpet odor. However, in the process, the reaction produced a variety of aldehydes, and the total concentration of organic chemicals in the air increased rather than decreased after the introduction of ozone (Weschler, et. al., b). In addition to aldehydes, ozone may also increase indoor concentrations of formic acid (Zhang and Lioy, ), both of which can irritate the lungs if produced in sufficient amounts. Some of the potential by-products produced by ozone&#;s reactions with other chemicals are themselves very reactive and capable of producing irritating and corrosive by-products (Weschler and Shields, , a, b). Given the complexity of the chemical reactions that occur, additional research is needed to more completely understand the complex interactions of indoor chemicals in the presence of ozone.
• Third, ozone does not remove particles (e.g., dust and pollen) from the air, including the particles that cause most allergies. However, some ozone generators are manufactured with an "ion generator" or "ionizer" in the same unit. An ionizer is a device that disperses negatively (and/or positively) charged ions into the air. These ions attach to particles in the air giving them a negative (or positive) charge so that the particles may attach to nearby surfaces such as walls or furniture, or attach to one another and settle out of the air. In recent experiments, ionizers were found to be less effective in removing particles of dust, tobacco smoke, pollen or fungal spores than either high efficiency particle filters or electrostatic precipitators. (Shaughnessy et al., ; Pierce, et al., ). However, it is apparent from other experiments that the effectiveness of particle air cleaners, including electrostatic precipitators, ion generators, or pleated filters varies widely (U.S. EPA, ).

There is evidence to show that at concentrations that do not exceed public health standards, ozone is not effective at removing many odor-causing chemicals.

• In an experiment designed to produce formaldehyde concentrations representative of an embalming studio, where formaldehyde is the main odor producer, ozone showed no effect in reducing formaldehyde concentration (Esswein and Boeniger, ). Other experiments suggest that body odor may be masked by the smell of ozone but is not removed by ozone (Witheridge and Yaglou, ). Ozone is not considered useful for odor removal in building ventilation systems (ASHRAE, ).
• While there are few scientific studies to support the claim that ozone effectively removes odors, it is plausible that some odorous chemicals will react with ozone. For example, in some experiments, ozone appeared to react readily with certain chemicals, including some chemicals that contribute to the smell of new carpet (Weschler, b; Zhang and Lioy, ). Ozone is also believed to react with acrolein, one of the many odorous and irritating chemicals found in secondhand tobacco smoke (US EPA, ).

If used at concentrations that do not exceed public health standards, ozone applied to indoor air does not effectively remove viruses, bacteria, mold, or other biological pollutants.

• Some data suggest that low levels of ozone may reduce airborne concentrations and inhibit the growth of some biological organisms while ozone is present, but ozone concentrations would have to be 5 - 10 times higher than public health standards allow before the ozone could decontaminate the air sufficiently to prevent survival and regeneration of the organisms once the ozone is removed (Dyas, et al.,; Foarde et al., ).
• Even at high concentrations, ozone may have no effect on biological contaminants embedded in porous material such as duct lining or ceiling tiles (Foarde et al, ). In other words, ozone produced by ozone generators may inhibit the growth of some biological agents while it is present, but it is unlikely to fully decontaminate the air unless concentrations are high enough to be a health concern if people are present. Even with high levels of ozone, contaminants embedded in porous material may not be affected at all.

If I Follow Manufacturers' Directions, Can I be Harmed?

Results of some controlled studies show that concentrations of ozone considerably higher than these standards are possible even when a user follows the manufacturer&#;s operating instructions.

There are many brands and models of ozone generators on the market. They vary in the amount of ozone they can produce. In many circumstances, the use of an ozone generator may not result in ozone concentrations that exceed public health standards. But many factors affect the indoor concentration of ozone so that under some conditions ozone concentrations may exceed public health standards.

• In one study (Shaughnessy and Oatman, ), a large ozone generator recommended by the manufacturer for spaces "up to 3,000 square feet," was placed in a 350 square foot room and run at a high setting. The ozone in the room quickly reached concentrations that were exceptionally high--0.50 to 0.80 ppm which is 5-10 times higher than public health limits (see Table 1.)
• In an EPA study, several different devices were placed in a home environment, in various rooms, with doors alternately opened and closed, and with the central ventilation system fan alternately turned on and off. The results showed that some ozone generators, when run at a high setting with interior doors closed, would frequently produce concentrations of 0.20 - 0.30 ppm. A powerful unit set on high with the interior doors opened achieved values of 0.12 to 0.20 ppm in adjacent rooms. When units were not run on high, and interior doors were open, concentrations generally did not exceed public health standards (US EPA, ).
• The concentrations reported above were adjusted to exclude that portion of the ozone concentration brought in from the outdoors. Indoor concentrations of ozone brought in from outside are typically 0.01- 0.02 ppm, but could be as high as 0.03 - 0.05 ppm (Hayes, ; U.S. EPA, b; Weschler et al., , ; Zhang and Lioy; ). If the outdoor portion of ozone were included in the indoor concentrations reported above, the concentrations inside would have been correspondingly higher, increasing the risk of excessive ozone exposure.
• None of the studies reported above involved the simultaneous use of more than one device. The simultaneous use of multiple devices increases the total ozone output and therefore greatly increases the risk of excessive ozone exposure.

Why is it Difficult to Control Ozone Exposure with an Ozone Generator?

The actual concentration of ozone produced by an ozone generator depends on many factors. Concentrations will be higher if a more powerful device or more than one device is used, if a device is placed in a small space rather than a large space, if interior doors are closed rather than open and, if the room has fewer rather than more materials and furnishings that adsorb or react with ozone and, provided that outdoor concentrations of ozone are low, if there is less rather than more outdoor air ventilation.

The proximity of a person to the ozone generating device can also affect one&#;s exposure. The concentration is highest at the point where the ozone exits from the device, and generally decreases as one moves further away.

Manufacturers and vendors advise users to size the device properly to the space or spaces in which it is used. Unfortunately, some manufacturers&#; recommendations about appropriate sizes for particular spaces have not been sufficiently precise to guarantee that ozone concentrations will not exceed public health limits. Further, some literature distributed by vendors suggests that users err on the side of operating a more powerful machine than would normally be appropriate for the intended space, the rationale being that the user may move in the future, or may want to use the machine in a larger space later on. Using a more powerful machine increases the risk of excessive ozone exposure.

Ozone generators typically provide a control setting by which the ozone output can be adjusted. The ozone output of these devices is usually not proportional to the control setting. That is, a setting at medium does not necessarily generate an ozone level that is halfway between the levels at low and high. The relationship between the control setting and the output varies considerably among devices, although most appear to elevate the ozone output much more than one would expect as the control setting is increased from low to high. In experiments to date, the high setting in some devices generated 10 times the level obtained at the medium setting (US EPA, ). Manufacturer&#;s instructions on some devices link the control setting to room size and thus indicate what setting is appropriate for different room sizes. However, room size is only one factor affecting ozone levels in the room.

In addition to adjusting the control setting to the size of the room, users have sometimes been advised to lower the ozone setting if they can smell the ozone. Unfortunately, the ability to detect ozone by smell varies considerably from person to person, and one&#;s ability to smell ozone rapidly deteriorates in the presence of ozone. While the smell of ozone may indicate that the concentration is too high, lack of odor does not guarantee that levels are safe.

At least one manufacturer is offering units with an ozone sensor that turns the ozone generator on and off with the intent of maintaining ozone concentrations in the space below health standards. EPA is currently evaluating the effectiveness and reliability of these sensors, and plans to conduct further research to improve society&#;s understanding of ozone chemistry indoors. EPA will report its findings as the results of this research become available.

Can Ozone be Used in Unoccupied Spaces?

Ozone has been extensively used for water purification, but ozone chemistry in water is not the same as ozone chemistry in air. High concentrations of ozone in air, when people are not present, are sometimes used to help decontaminate an unoccupied space from certain chemical or biological contaminants or odors (e.g., fire restoration). However, little is known about the chemical by-products left behind by these processes (Dunston and Spivak, ). While high concentrations of ozone in air may sometimes be appropriate in these circumstances, conditions should be sufficiently controlled to insure that no person or pet becomes exposed. Ozone can adversely affect indoor plants, and damage materials such as rubber, electrical wire coatings and fabrics and art work containing susceptible dyes and pigments (U.S. EPA, a).

What Other Methods Can Be Used to Control Indoor Air Pollution?

The three most common approaches to reducing indoor air pollution, in order of effectiveness, are:

1. Source Control: Eliminate or control the sources of pollution;
2. Ventilation: Dilute and exhaust pollutants through outdoor air ventilation and
3. Air Cleaning: Remove pollutants through proven air cleaning methods.

Of the three, the first approach &#; source control &#; is the most effective. This involves minimizing the use of products and materials that cause indoor pollution, employing good hygiene practices to minimize biological contaminants (including the control of humidity and moisture, and occasional cleaning and disinfection of wet or moist surfaces), and using good housekeeping practices to control particles.

The second approach &#; outdoor air ventilation &#; is also effective and commonly employed. Ventilation methods include installing an exhaust fan close to the source of contaminants, increasing outdoor air flows in mechanical ventilation systems, and opening windows, especially when pollutant sources are in use.

The third approach &#; air cleaning &#; is not generally regarded as sufficient in itself, but is sometimes used to supplement source control and ventilation. Air filters, electronic particle air cleaners and ionizers are often used to remove airborne particles, and gas adsorbing material is sometimes used to remove gaseous contaminants when source control and ventilation are inadequate.

See Additional Resources section below for more detailed information about these methods.

Conclusions

Whether in its pure form or mixed with other chemicals, ozone can be harmful to health.

When inhaled, ozone can damage the lungs. Relatively low amounts of ozone can cause chest pain, coughing, shortness of breath and, throat irritation. It may also worsen chronic respiratory diseases such as asthma as well as compromise the ability of the body to fight respiratory infections.

Some studies show that ozone concentrations produced by ozone generators can exceed health standards even when one follows manufacturer&#;s instructions.

Many factors affect ozone concentrations including the amount of ozone produced by the machine(s), the size of the indoor space, the amount of material in the room with which ozone reacts, the outdoor ozone concentration, and the amount of ventilation. These factors make it difficult to control the ozone concentration in all circumstances.

Available scientific evidence shows that, at concentrations that do not exceed public health standards, ozone is generally ineffective in controlling indoor air pollution.

The concentration of ozone would have to greatly exceed health standards to be effective in removing most indoor air contaminants. In the process of reacting with chemicals indoors, ozone can produce other chemicals that themselves can be irritating and corrosive.

Recommendation

The public is advised to use proven methods of controlling indoor air pollution. These methods include eliminating or controlling pollutant sources, increasing outdoor air ventilation and using proven methods of air cleaning.

Additional Resources

See Indoor Air Quality Publications

Publications

Information Sources

California Department of Health Services, Indoor Air Quality Program, DHS-IAQ Program Assistance Line: (510) 620-, Fax: (510) 620-

Federal Trade Commission, Consumer Response Center, (202) 326-.

U.S. Consumer Product Safety Commission,or call Consumer Hotline, English/Spanish: (800) 638-, Hearing/Speech Impaired: (800) .

The Association of Home Appliance Manufacturers (AHAM) has developed an American National Standards Institute (ANSI)-approved standard for portable air cleaners (ANSI/AHAM Standard AC-1-). This standard may be useful in estimating the effectiveness of portable air cleaners. Under this standard, room air cleaner effectiveness is rated by a clean air delivery rate (CADR) for each of three particle types in indoor air: tobacco smoke, dust and pollen. Only a limited number of air cleaners had been certified under this program when this document was written.

A listing of AHAM-certified room air cleaners and their CADRs can be obtained from Aham Verifide

Association of Home Appliance Manufacturers (AHAM)
(202) 872-

If you want to learn more, please visit our website home ozone generator factories.

Bibliography

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