According to Dr. James T. Li, M.D., a board-certified asthma and allergy specialist chair of the Division of Allergic Diseases in the Department of Internal Medicine, believes that ozone air purifiers cannot improve asthma symptoms. Instead, they may aggravate asthma symptoms, such as coughing, wheezing and shortness of breath. As a result, the American Lung Association does not recommend using such air purifiers.

These air purifiers release ozone molecules, each of which is comprised of three oxygen atoms. One of atom separates from the other two atoms, and combines with molecules of a few other pollutants. Due to this change in chemical composition, the concentration of some pollutants in the air decline – but very insignificantly. However, several substances, after reacting with ozone, turn into toxic pollutants like formaldehydes.

In addition, the ozone released by the air purifiers is a “potent irritant” that can cause inflammation of the bronchial tubes of the lungs, resulting in chest pain, difficulty in breathing, coughing, throat infection and respiratory infections. In addition, it can increase the lungs’ sensitivity to allergens.

A high concentration of ozone in the air (greater than 0.08 ppm) is dangerous, especially for children. A University of California Davis study found that “high levels of ozone can change lung development, making them hypersensitive to allergens”.