Inhaling ozone, even in small amounts, can irritate the lungs. Specific effects may include throat irritation, coughing, chest pain and shortness of breath, as well as an increased risk of respiratory infections.

Some ozone air purifiers are made with an ion generator, sometimes called an ionizer, in the same unit. You can also buy ionizers as separate units. Ionizers do remove particles from the air, causing them to attach to nearby surfaces or to each other and settle out of the air — but they may generate unwanted ozone.

Air filters that remove small particles — such as high-efficiency particulate air (HEPA) filters — are effective in removing allergens from the air, without posing any ozone concerns. To work effectively, filters need to be cleaned or replaced regularly, according to the manufacturer’s instructions.