Review on Greentech Environmental pureAir 500: The Ultimate Portable Air Purifier and Cleaner for Home, Office, and Bedroom, Ideal for Up to 850 Sq. Ft., Eliminates Stubborn Odors with Ease! by Leah Nelson

I have had very severe indoor allergies and have tested many cleaners. This was small, but filtered a lot of airspace. You can actually tell when the air is clean, which is a big plus. I haven't had any internal allergies since using it and usually leave it on when I sleep. I'll be buying another one for my living room soon. Good product!