The Dyson humidifier kills 99.9% of bacteria in the water before projecting it. The way it kills bacteria is by using ultraviolet light.
Thanks to it killing 99.9% of bacteria it safely projects hygienic air into a 172 sq/ft room. You won't have to worry about over doing it since the Dyson measures temperature and humidity and adjusts to keep things comfortable. This humidifier can provide up to 18 hours of continuos use on one tank of water.