AeraSense is a new technology with the accuracy and performance of a professional sensor. It senses particles smaller than PM2.5, removes up to 99.9% of viruses and aerosols from the air* adapting automatically with real time feedback. When in Silent Mode, the Purifier turns down its fan speed and noise level to allow a comfortable night's sleep. The numerical PM2.5 indicator and the 4-step color ring provides real time feedback of your indoor air quality. Both AQI and the light on the UI can be dimmed and/or turned off avoid light disturbance for consumers. 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. Removes aerosols including those containing respiratory virus, from the air which passes through the filter. It also sanitizes the air by removing 99.9% of aerosols from the air that may contain viruses.* 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. 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. 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. Aerodynamic architecture boosts efficient airflow. Ecarf (EU) and Airmid (US) Certified.