The Dyson Purifier Hot+Cool™ Gen1 purifying fan automatically senses, captures and traps pollutants to purify your whole room.¹ It heats or cools the air, while removing 99.97% of particles as small as 0.3 microns.³¹Tested per Dyson internal test standards for whole-room air projection (DTM108) and purification coverage (TM-003711).²Particle challenge by DEHS oil specified in EN1822 within a chamber specified in ASTM F3150. Tested in Max Mode for whole machine efficiency above 99.95%. Gas capture rates vary.³Tested per ISO 29463.