Where you place your purifier varies. You may want to place it in a room where you’re particularly concerned about the air quality or know there is a higher concentration of air pollutants. Or you may want to place it in the room where you spend most of your time.  Regardless, make sure you place your air filter in an open space. Homer recommends that you read your air purifier’s instruction manual for any specifics on placements. “Most manufacturers will tell you to place the purifier on a flat surface, out of direct sunlight, so it doesn't overheat, and away from the walls, so air can circulate around it freely," she adds. "Some may also caution you to keep the unit away from TV and electronics, as they may cause electromagnetic interference that causes the purifier to malfunction.”