The main selling point of ionic air purifiers is the silence with which they are said to remove particles from the air. This is due to the lack of circulating fan in this type of air cleaner, as the Sharper Image air purifier, the original ionic cleaner, relies on electrostatic plates to circulate the air. Independent tests have shown, however, that this reliance is somewhat misplaced while a fan-assisted air purifier can process a room s air within one minute, this ionic air purifier has a turnover rate move only an estimated couple of cubic meters per hour. cnn money