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.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.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.