Ozone generators can remove stubborn odors, but ozone is a lung irritant. This guide explains the risks in plain English and gives a simple routine for using one without putting people, pets or plants in danger.
This is general information, not medical or legal advice. For health concerns see a doctor, and for rules in your state check your state government's website.
What ozone does to your body
The EPA notes that breathing ozone can irritate the throat and airways, cause coughing, chest pain and shortness of breath, and worsen asthma and other lung diseases. Children, older adults and people with respiratory conditions are more sensitive.
Ozone also has a sharp, clean smell, like the air after a thunderstorm. If you can smell it, you are breathing it.
What the rules say
OSHA sets a workplace limit of 0.1 ppm averaged over eight hours. The EPA advises against using ozone generators as air cleaners in occupied spaces. California requires indoor air cleaning devices sold in the state to meet an emission limit for ozone, and some other states have related rules.
These rules exist because the ozone levels needed to remove odors can exceed what is safe to breathe.
Ozone can react with other chemicals
Ozone reacts with other chemicals indoors, including those from paint, cleaners, fragrances and new furniture. The reaction can form other irritants. That is another reason to treat only empty spaces and to ventilate afterwards.
A safe routine in six steps
Remove all people, pets and plants. Close doors and windows to keep the ozone in the treated space. Plug in the unit and set the timer. Leave the building or at least stay far from the room. After the cycle ends, open windows and run a fan. Keep out until the sharp ozone smell is gone.
Follow the manual of your unit, and keep the first run short.
Materials and belongings
Ozone can age rubber, some plastics, elastic and old fabrics, and it can fade some artwork and dyes over time. Move valuable or delicate items out before treating a room, and avoid repeated heavy treatments.
When to choose a HEPA purifier instead
If your goal is cleaner air while you are in the room, a HEPA air purifier is the right tool. It captures dust, pollen and smoke particles without producing ozone. Choose models that state they do not emit ozone.
Frequently asked questions
Is it safe to run an ozone generator in a bedroom while sleeping?
No. Do not run one in a room where anyone is present or sleeping.
How long should I wait before going back in?
Follow your manual. As a rule, ventilate with open windows and fans, and stay out until the sharp ozone smell is gone. When in doubt, wait longer.
Do ozone generators kill mold or viruses?
We do not make or repeat those claims. Ozone does not remove the source of a mold problem, and listing claims about disinfecting are not verified here.
Is it legal to sell or buy ozone generators in California?
California regulates ozone emissions from indoor air cleaning devices sold in the state. Check current rules on the California Air Resources Board website and the details of the listing.
