Remember to keep your air purifier clean, and change your HEPA filter as recommended to ensure that it keeps running correctly. You can buy reusable filters that only require cleaning, but these do have a limited life expectancy and will still need to be completely replaced eventually.
Try to adhere to the room-size specifications that come with your air purifier for the most effective air cleaning possible. If placed in rooms with high foot traffic or rooms too large for their capacity, air purifiers will not clear the air of irritants as well as if they are used correctly. Don't forget to wipe down the outside of your machine with a dry or slightly damp cleaning cloth.
Dr. Lee also recommends keeping your home clean to reduce the burden on the air purifier. "Reduce environmental triggers by hoovering twice a week or more with a hoover with a HEPA filter." she advises. "Don’t smoke in the house or anywhere near the bedroom. Take your shoes off as soon as you come into the house to avoid treading allergens into the carpets and up the stairs. Keep the house clean by regularly washing the basins, baths and showers with an anti-mold cleaner."