The Dyson Purifier Big+Quiet Formaldehyde is our biggest purifier yet, engineered from the ground up, to evenly purify large spaces. Cone aerodynamics creates a condensed jet of air to project purified air over 32 feet. Quietly. An advanced 360 Hepa H13 grade filter captures allergens and 99.97% of fine particles. Removes gases and odors.² Destroys formaldehyde, permanently. Testing for PM2.5 purification completed in a large testing chamber following relevant Dyson testing methods. Results may vary in practice.²Tested to Jem 1467 (acetic acid, acetaldehyde, ammonia), Gb/T18801 (formaldehyde, benzene) and Dtm-003282 (NO2). Gas capture rates vary. Third party full machine testing based on Gb/T 18801-2022 formaldehyde cumulative clean mass testing with continuous injection until plateau of formaldehyde Cadr is achieved. Results may vary in practice. Particle challenge by Dehs oil specified in EN1822 within a chamber specified in Astm F3150.