An official United States government website Using official websites. Government A. The.gov website belongs to an official government organization in the United States. Several brands of ozone generators have the EPA establishment number on their packaging.
This number helps the EPA identify the specific facility that produces the product. Viewing this number does not imply EPA approval nor does it in any way suggest that the EPA has determined that the product is safe or effective. Ozone generators, sold as air filters, intentionally produce ozone gas. Often, sellers of ozone generators make statements and distribute material that make the public believe that these devices are always safe and effective in controlling indoor air pollution.
For nearly a century, health professionals have refuted these claims (Sawyer, et. To 1913; Salls, 1927; Boeniger, 1995; American Lung Association, 1997; Al-Ahmady, 199. The purpose of this document is to provide accurate information on the use of ozone-generating devices in occupied indoor spaces. This information is based on the most credible scientific evidence available today. Some vendors suggest that these devices have been approved by the federal government for use in occupied spaces.
To the contrary, NO federal government agency 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. Department of State. UU.
Environmental Protection Agency to produce this public information document. Ozone is a molecule made up of three oxygen atoms. Two oxygen atoms form the basic oxygen molecule, the oxygen we breathe and which is essential for life. The third oxygen atom can detach from the ozone molecule and rejoin the molecules of other substances, thus altering their chemical composition.
It is this ability to react with other substances that forms the basis of manufacturers' claims. 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 organic material similar to that which makes up the body and, potentially, cause harmful health consequences. When inhaled, ozone can damage the lungs. Relatively low amounts can cause chest pain, cough, shortness of breath, and throat irritation.
Ozone can also worsen chronic respiratory diseases, such as asthma, and compromise the body's ability to fight respiratory infections. People vary widely in their susceptibility to ozone. Healthy people, as well as those with breathing difficulties, may experience respiratory problems when exposed to ozone. Exercise during exposure to ozone causes more ozone to be inhaled and increases the risk of harmful respiratory effects.
Recovery from harmful effects may occur after brief exposure to low levels of ozone, but the health effects may be more damaging and recovery may be less safe at higher levels or from longer exposures (U.S. EPA, 1996a, 1996b). The Food and Drug Administration (FDA) requires that the ozone production of indoor medical devices does not exceed 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 for Occupational Safety and Health (NIOSH) recommends a maximum limit of 0.10 ppm, which should not be exceeded at any time. The EPA's national ambient air quality standard for ozone is an 8-hour average outdoor maximum concentration of 0.08 ppm. The U.S. UU.
,. The Environmental Protection Agency (EPA) will distinguish between ozone in the upper and lower atmosphere. Ozone in the upper atmosphere, called stratospheric ozone, helps filter harmful ultraviolet radiation from the sun. While 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 caused by the interaction of sunlight with certain chemicals released into the environment (for example,. These harmful concentrations of ozone in the atmosphere are often accompanied by high concentrations of other pollutants, such as nitrogen dioxide, fine particles and hydrocarbons. Whether pure or mixed with other chemicals, ozone can be harmful to health. Available scientific evidence shows that, at concentrations that do not exceed public health standards, ozone has little potential to remove contaminants from indoor air.
Some manufacturers or vendors suggest that ozone will render almost all chemical contaminants harmless by producing a chemical reaction whose only by-products are carbon dioxide, oxygen and water. Evidence shows that, at concentrations that do not exceed public health standards, ozone is not effective in eliminating many chemicals that cause bad odors. When used in concentrations that do not exceed public health standards, ozone applied to indoor air does not effectively eliminate viruses, bacteria, mold, or other biological contaminants. The results of some controlled studies show that ozone concentrations considerably higher than these standards are possible even if the 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. However, many factors affect indoor ozone concentration, so that, under some conditions, ozone concentrations can exceed public health standards.
The actual concentration of ozone produced by an ozone generator depends on many factors. The concentrations will be higher if a more powerful device or more than one device is used, if the device is placed in a small space rather than in a large space, if the interior doors are closed rather than open and, if the room has fewer materials and furniture that adsorb or react with ozone and, provided that ozone concentrations outside are low, if there is less ventilation of the outside air rather than more. A person's proximity to the ozone-generating device can also affect exposure. The concentration is highest at the point where the ozone leaves the device and generally decreases as you move away.
Manufacturers and vendors advise users to size the device appropriately for the space or spaces in which it is used. Unfortunately, some manufacturers' recommendations for appropriate sizes for particular spaces have not been precise enough to ensure that ozone concentrations do not exceed public health limits. In addition, some publications distributed by vendors suggest that users are wrong to operate a more powerful machine than would normally be appropriate for the intended space, since the user could move in the future or may want to use the machine in a larger space later. Using a more powerful machine increases the risk of excessive exposure to ozone.
In addition to adjusting the control settings to the size of the room, users have sometimes been advised to lower their ozone settings if they can smell the ozone. Unfortunately, the ability to detect ozone by smell varies considerably from person to person, and the ability to smell ozone deteriorates rapidly in the presence of ozone. While the smell of ozone may indicate that the concentration is too high, the lack of odor does not guarantee that levels are safe. At least one manufacturer offers units with an ozone sensor that turns the ozone generator on and off with the intention of keeping ozone concentrations in space below health standards.
The EPA is currently evaluating the effectiveness and reliability of these sensors and plans to carry out more research to improve society's understanding of indoor ozone chemistry. The EPA will report its findings as the results of this investigation become available. 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 moisture control and occasional cleaning and disinfection of wet or damp surfaces), and using good cleaning practices to control particles.
The second approach: outdoor air ventilation is also effective and is commonly used. Ventilation methods include installing an exhaust fan near the source of contaminants, increasing outdoor airflows in mechanical ventilation systems, and opening windows, especially when using pollutant sources. The third approach: air purification is generally not considered sufficient in itself, but it is sometimes used to supplement source and ventilation control. Air filters, electronic particulate air filters, and ionizers are often used to remove airborne particles, and gas adsorbent material is sometimes used to remove gaseous contaminants when source control and ventilation are inadequate.
See the Additional Resources section below for more detailed information on these methods. Whether in its pure form or mixed with other chemicals, ozone can be harmful to health. Relatively low amounts of ozone can cause chest pain, coughing, shortness of breath, and throat irritation. It can also worsen chronic respiratory diseases, such as asthma, and compromise the body's ability to fight respiratory infections.
Some studies show that the ozone concentrations produced by ozone generators can exceed health standards, even if the manufacturer's instructions are followed. Many factors affect ozone concentrations, including the amount of ozone produced by machines, the size of the interior space, the amount of material in the room with which ozone reacts, the concentration of outdoor ozone, and the amount of ventilation. These factors make it difficult to control ozone concentration under all circumstances. Available scientific evidence shows that, at concentrations that do not exceed public health standards, ozone is generally not effective in controlling indoor air pollution.
The concentration of ozone would have to far exceed health standards to be effective in eliminating most indoor air pollutants. In the process of reacting with indoor chemicals, ozone can produce other chemicals that, in themselves, can be irritating and corrosive. The public is encouraged to use proven methods to control indoor air pollution. These methods include eliminating or controlling sources of contaminants, increasing outdoor air ventilation, and using proven methods of cleaning the air.
See publications on indoor air quality You can get a list of air filters for AHAM-certified rooms and their CADRs from the Verified Association of Home Appliance Manufacturers (AHAM) (20 872-5955). I especially appreciate your comprehensive and unbiased review of air ionization technology and hope to receive an equally unbiased concern in response to a question I have, as this topic also seems to be in the realm of controversy). Air ionizers are designed to help provide cleaner air and they do so by using ionized particles. Today's air ionizers are often equipped with ozone sensors that help monitor, suppress and prevent high levels of ozone from escaping into the air you breathe.
I recently changed all of the HVAC units in my house and installed air purifiers in each unit (3 in total), 2 on the main floor (approximately 3500 square feet) and one in the basement (1500 square feet). That said, in my experience, the vast majority of air purifying power comes from the unit's airflow and the HEPA filter. However, ozone-specific air purifiers are not safe at any level to keep humans around when they are operating and can take several hours (or even days) to fully ventilate. Suffice to say, the safest option would be to avoid any air purifier with an ionizer of any type or that alters the chemistry of the air in any way.
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