Ozone filters: Do they remove allergens from the air?

Despite manufacturer claims, ozone filters don't remove particles from the air, including those that cause most allergies. In fact, inhaled ozone may even make asthma worse.

Ozone generators sold as air purifiers intentionally produce the gas ozone. Ozone is a molecule made of three atoms of oxygen. Two of these atoms form the basic oxygen molecule. The third atom can detach from the ozone molecule and reattach to molecules of other substances, changing their chemical composition. This is the basis of manufacturer claims that ozone "purifies" the air. But inhaling ozone — even in small amounts — can be harmful to lung tissue. Inhaled ozone may cause throat irritation, coughing, chest pain and shortness of breath.

Some ozone filters are made with an ion generator or "ionizer" in the same unit. You can also buy ionizers as separate units. Ionizers do take particles out of the air. Ions stick to particles, causing them to attach to nearby surfaces or to each other and settle out of the air. But ionizers don't work any better than high-efficiency particulate air (HEPA) filters or electrostatic filters in removing allergens from the air.