The Dust That Won't Die

There is something about an old house that keeps dust pumping into every nook and cranny. This phenomenon is enhanced with the level of construction and renovation that goes on in our home. However, the construction has been stopped for months. I spent several days carefully cleaning up all traces of drywall and plaster dust and renovation debris hoping it would alleviate the problem, yet the dust remains. I spend hours every week vacuuming, dusting, cleaning vents, etc only to see a layer of the gray shroud reappear almost instantly. Where does it all come from?