Dyson Purifier Cool PC2 De-NOx delivers whole-room purification and powerful cooling. Advanced air purification captures 50% more NO2. Removes odors and gases and continuously destroys formaldehyde. The fully sealed 3-stage filter system captures 99.97% of particles as small as 0.3 microns. The whole purifier, not just the filtration system, is fully sealed to HEPA H13 grade. Air Multiplier technology projects over 76 gallons per second of smooth yet powerful airflow.