Philips 1000 Series NightSense AC1211/20 50-Watt Room Air Purifier (White) Philips air purifier series 1000, with nightsense and vitashield ips (intelligent purification system) technology, automatically purifies your indoor air quality. Extra-thick nanoprotect true hepa filter captures 99.97% Of particles that pass through the filters, effectively reducing allergens, gases and odors. It is ideal for a room with an applicable room size up to 677 sq.Ft. And 100% ozone free with no harmful chemicals or ozone released (natural filtration technology).