The DeLonghi AC230 Energy Star Air Purifier with Ionizer incorporates the latest technological features for quiet, home air filtration and is suitable for rooms up to 220 sq ft. It has six layers of air filtration including the pre-filter, HEPA filter, active carbon filter, NANO silver filter, photo catalytic filter with UVC lamp and ionizer with on/off function cleaning the air and removing impurities down to a size of 0.3 microns including dust, pollen, cigarette smoke and car exhaust fumes. DeLonghi's AQS air quality system uses a unique lighted sensor system to give you visible feedback on the room's air quality (orange for bad, green for satisfactory and blue for good) adjusting the fan speed as the room's air quality changes. Convenience features include a sensor touch LED control panel, timer (1, 3, 4 or 8 hours) and filter indicator.