June 15, 2022

Ozone Generators Sold as Air Purifiers

Ozone generators intentionally produce ozone gas to purify the air in indoor spaces. The manufacturers and vendors of ozone generators claim the units are safe and effective indoor air purifiers. EPA has developed an ozone generators webpage to address health impacts of these generators and to provide accurate information on ozone.

Many credible scientific studies evaluate the health effects of ozone inhalation. Ozone (O3) is much more reactive than a standard oxygen molecule (O2) and when inhaled can damage the lungs and aggravate chronic respiratory diseases such as asthma. Even breathing in low amounts of ozone can cause chest pain, coughing, shortness of breath, and throat irritation.

Studies conducted on the amount of ozone produced by ozone generating air purifiers indicate ozone concentrations are difficult to control. Many variables affect ozone concentrations, including the indoor space size, ventilation, amount of material in the air that reacts with ozone, and outdoor ozone concentration. Overall, when using ozone generators in indoor spaces, EPA determined it is difficult to control the ozone concentration in all circumstances, leading to the production of unsafe levels of ozone.

Other studies prove ozone is ineffective as an air purifier when concentrations are below the public health standards. Rather, the concentration of ozone would have to greatly exceed health standards to be effective, making it unsafe to breathe. The agency recommends using proven methods of indoor air purification to improve the air quality in indoor spaces like eliminating or controlling pollutant sources and increasing outdoor air ventilation.


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