Is Ozone Bad for You?
According to the EPA, breathing it can be. The EPA says that when inhaled, ozone can damage the lungs, and that relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. It says ozone may also worsen chronic respiratory diseases such as asthma and compromise the body's ability to fight respiratory infections.
That matters most for ozone generators sold as air cleaners. The EPA says available scientific evidence shows that at concentrations that do not exceed public health standards, ozone has little potential to remove indoor air contaminants and does not effectively remove viruses, bacteria, mold or other biological pollutants. It also says that, contrary to what some vendors suggest, no agency of the federal government has approved these devices for use in occupied spaces.
California regulates them. Under Assembly Bill 2276, the California Air Resources Board adopted a regulation limiting the ozone produced by indoor air cleaning devices, which it says became final on October 18, 2008. CARB says portable indoor air cleaners sold in California must be certified, that electronic air cleaners must meet an ozone emission limit of 0.050 parts per million, and that as of October 2020 electronic in-duct air cleaners are covered too.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceThe EPA says inhaled ozone can damage the lungs, and relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. US EPA ↗
- Government sourceThe EPA says ozone may worsen chronic respiratory diseases such as asthma and compromise the body's ability to fight respiratory infections. US EPA ↗
- Government sourceThe EPA says that at concentrations that do not exceed public health standards, ozone has little potential to remove indoor air contaminants and does not effectively remove viruses, bacteria, mold or other biological pollutants. US EPA ↗
- Government sourceThe EPA says no agency of the federal government has approved ozone generators for use in occupied spaces, contrary to what some vendors suggest. US EPA ↗
- Regulatory filingUnder California Assembly Bill 2276, CARB adopted a regulation limiting ozone produced by indoor air cleaning devices, which CARB says became final on October 18, 2008. California Air Resources Board ↗
- Regulatory filingCARB says portable indoor air cleaners sold in California must be certified, electronic air cleaners must meet an ozone emission limit of 0.050 ppm, and as of October 2020 electronic in-duct air cleaners are also covered. California Air Resources Board ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.