 uh allergens it works for everything and it works fast and it works very quietly which i really appreciate because right now i got the ac in my house i got one of those units it's so loud i can't even hear the television so what i love about the thunderstorm is i turn it on and i can't even hear it but i know it's working the thunderstorm starts working in seconds with no filters to buy place a thunderstorm in your bedroom your basement your family room your kitchen they even make great gifts you