Ozone is a gas that occurs both in the Earth's upper atmosphere and at ground level. It can be "good" or "bad" for people’s health and for the environment, depending on its location in the atmosphere. When inhaled, ozone can damage the lungs. Relatively low amounts can cause chest pain, coughing, shortness of breath, and throat irritation. Healthy people, and those with respiratory difficulties, can experience breathing problems when exposed to ozone.
Ozone generators that are sold as air cleaners intentionally produce the gas ozone. Manufacturers suggest that ozone will render almost every chemical contaminant harmless. This is misleading. Available scientific evidence shows that ozone, at concentrations that do not exceed public health standards, has little potential to remove indoor air contaminants.