What exactly are you trying to filter/keep out? Dust? Gases? Everything?

I don't think I've ever heard of a residential home being overpressured, unless it was a HVAC kind of mistake. Not that I'm an expert, but if you ever try to go down that path, you need to keep in mind that air is meant to circulate a certain way through a house. If the airflow is altered, it could lead to moisture build up and mold in places you wouldn't expect.