Philips' Series 3000 air purifier features upgraded VitaShield IPS technology to filter ultra-fine particles as small as 0.02um, and 99.97% of common airborne allergens. Advanced AeraSense technology gives you reassurance by displaying real time indoor air quality, and extra thick NanoProtect removes 99.9% of bacteria and some viruses, like asH1N1. It also provides protection from harmful gases like formaldehyde, toluene and TVOC, and allergen mode detects the slightest change in air quality and boosts cleaning performance to accommodate.