Dyson Air Purifier Hot+Cool Fan Formaldehyde HP09 Smart Tower in White/GoldDyson's latest purifiers combine intelligent sensing with an advanced filtration system. Three phases of purification sit within a fully sealed filtration and airflow system. So what goes inside, stays inside. A solid state formaldehyde sensor and a unique catalytic filter detect and continuously destroy formaldehyde. Then powerful Air Multiplier technology purifies, heats the whole room and cools you. Third party full machine testing based on GB T