The Humidify+Cool contains a HEPA filtration system and also a independent carbon filter detects formaldehyde. I guess it may be due partly to my obsession with clean air, but, to this point, the Dyson has documented good air excellent anytime I’ve checked in–the one exceptions being soon after I’ve lit https://infopagex.com/story2202829/fascination-about-air-purifier-for-travel