When it’s time to change your filter, make sure that you always have a replacement ready. The Safety 1st True HEPA Replacement Air Purifier Filter removes 99.97% of airborne particles, so there is less dust, pollen, and pet dander in the air. With less contaminants in the air your child’s nursery, or any room where you place the air purifier, will have cleaner and fresher air to breathe.