Healthier Air, Always AeraSense, making the invisible visible 25-79m2 room size Numerical air quality feedback Low noise at Sleep Mode (20.5dba) - soft as a whisper When in Silent Mode, the Purifier turns down its fan speed and noise level to allow a comfortable night's sleep. Smart light control: adjust light to suit your preference Both AQI and the light on the UI can be dimmed and/or turned off avoid light disturbance for consumers. 3 auto modes: General, Allergen, and Bacteria & Virus The Philips Air Purifier has 3 automatic purification settings: a General mode, an extra-sensitive Allergen mode, and an extra-powerful bacteria and virus mode. You can choose your preferred mode to personalize and optimize your purification. Certified or tested by ECARF and Airmid* Certified or tested by ECARF and Airmid* Automatically monitors, reacts & purifiers the air AeraSense is a sensor that accurately identifies fine particles that are even smaller than PM2.5 (including most common indoor airborne allergens). It then processes this information to ensure that the purifier’s settings are at the ideal level for current air conditions, and for continuous re-assurance. Then gives you feedback of real time indoor air quality by showing PM2.5 level. VitaShield naturally purifies UFP as small as 0.02microns Vitashield IPS with its aerodynamic design and NanoProtect Filter has a boosted clean air delivery rate up to 344 m3/hr* (according to China GB/T 18801-2015). It can effectively remove ultra-fine particles as small as 20nm, effectively reduce harmful gases such as formaldehyde, TVOC and odor. Removes up to 99.9% bacteria and virus*. Aerodynamic architecture boosts efficient airflow Aerodynamic architecture boosts efficient airflow Healthy air lock and alert for filter replacement The filter lifetime is accurately calculated based on indoor pollution level, air flow and operation time. The healthy air protect alert lets you know promptly when it is time to replace the filter. If the filter is not replaced promptly, the appliance stops functioning -to avoid ineffective purification. So you are assured of healthier air always. Four-step color indicator shows quality of air The 4-step color ring provide real time feedback of your indoor air quality.