The Cuboid: A DIY air purifier that's better than a box fan
http://imgur.com/a/u1Ti7You can also build your computer into an air filter like I did.I'm currently running MERV 13 filters and it pulls over 100 CFM at a very livable noise level, currently equipped with Noctua NF-A12x25 fans.The computer stays very cool but also incredibly clean.