Some companies and websites market devices called ozone machines or ozone generators by claiming that ozone is beneficial for human health or reduces indoor air pollution. There is no evidence to support these claims; in fact, the available evidence tends to indicate exactly the opposite, that high concentrations of ozone are dangerous for you. At least one couple has been sentenced to jail by a district court for marketing these devices as a treatment for a medical condition.
Each molecule of oxygen gas that you breathe contains two atoms of the element oxygen. Each molecule of ozone gas, by contrast, contains three atoms of oxygen. This combination is unstable and tends to react with a variety of carbon-based compounds. This high level of reactivity makes ozone very good at destroying germs during water treatment. Unfortunately, it also makes it dangerous to human health, since the ozone can react with molecules in your lungs in much the same way.
The U.S. Food and Drug Administration and the Code of Federal Regulations regard ozone as toxic and without any demonstrated medical use. According to the FDA, the concentrations of ozone you would need to kill bacteria and viruses are high enough they would also harm humans and other animals. Machines intended for household, office or health care center use that generate ozone at levels over 0.05 parts per million or are marketed using claims that they have medical benefits are banned by federal regulations.
When ozone reacts with molecules lining the interior of your lungs, it irritates the mucus membrane and can cause fluid to leak into the lungs -- a condition called pulmonary edema. Symptoms include chest pain, shortness of breath and coughing. Some people are more susceptible than others; people with respiratory system disorders like asthma are at especially high risk. The Environmental Protection Agency has found that some of the devices currently on the market can generate enough ozone to drive concentrations in your home up above safe levels.
There is no need or reason to install an ozone-producing device in your home. Many manufacturers of these devices claim that ozone can remove pollutants or germs or benefit human health in some way. There is no evidence to support these claims; in fact, the concentrations of ozone required to get rid of germs and pollutants are easily far more than enough to harm you and your family. You should be wary of manufacturers or websites that make these kinds of claims.