Ozone generators are products that use a chemical process to break apart molecules of oxygen gas to produce ozone gas. These products are sold as air purifiers that can effectively control indoor pollution, but there is no scientific evidence that this is true.
The U.S. Environmental Protection Agency states that not only are ozone generators ineffective at cleaning the air, but they may actually pose a potentially serious health risk. Although ozone is a compound made up of only oxygen molecules, it is nonetheless different from the oxygen gas that humans breathe. Short-term exposure to ozone can lead to chest pains and difficulty breathing, while long-term exposure or exposure to high levels of the gas can cause much more serious respiratory problems.
Ozone plays a vital role in the upper atmosphere, but it can be quite harmful to plant and animals if the gas occurs in higher concentrations in the lower atmosphere. For this reason, the EPA uses the phrase "good up high, bad nearby" when discussing ozone.
There are different methods these products use to generate ozone, but one of the most common is by splitting molecules of oxygen gas into single oxygen atoms. These single atoms then attach to one of the O2 molecules to form ozone.