I purchased an Alen air purifier for my son. His family was living with a mold problem in the basement that caused the whole house to smell musty. I purchased the filter that is designed to deal with this problem. My daughter in law noticed an immediate improvement in air quality hours after starting her purifier and I could smell the difference when I walked in the door! She also loves the compactness, style and pale green color that fits in perfectly with her open space upstairs area. Thanks for making their home so safe and healthy!