Electrostatic air cleaners work by passing air over an electrical charge. This causes particles in the air to stick to metal surfaces in it. It removes them from the breathing zone. These metal surfaces need to be cleaned.
Despite manufacturer’s claims, these air purifiers may not remove allergens from the air. Avoid any air purifiers that produce ozone. This is a gas that can irritate the respiratory tract including the lungs.
Air filters that remove small particles (e.g., high-efficiency particulate air (HEPA) filters) effectively remove allergens. These include pollen, mold spores, and animal dander, among others. These filters do not pose any ozone concerns. To work effectively, regularly clean or replace filters.
Finally, there is an excellent resource available: “Air Cleaners: What You Need to Know”. It includes information about the asthma & allergy friendly ® Certification Program. It helps people make informed decisions when purchasing products for their home.