Drywall dust is horrible. It is so horrible that some vacuum manufacturers instantly void your warranty if you use it for sucking up drywall dust.
Until some genius invents a better wall system, this fine, talcum powder-like byproduct (gypsum) of sanding drywall joints is a miserable fact of home remodeling life. Is there a way to reduce it in the first place?
Low-Dust Drywall Compound
Sanding with compound produces dust, but it is more like the sawdust you get from cutting wood. Heavier particles drop to the ground, rather than going airborne and floating to the farthest reaches of your house.
If cost is not an issue to you, low-dust drywall compound is your best bet.
Dry Sanding With Barrier and Negative Pressure
Barriers, made of sheet plastic available at any hardware store, are only a partial solution. Tape the plastic against floors, ceilings, and walls, separating the dusting zone from the area you want to remain clean.
If you never remove the barrier, and if the barrier has absolutely zero holes, the "clean area" should remain clean.
But even the tiniest hole in the plastic will, surprisingly, allow drywall dust into the clean area. Moving the plastic aside even once to pass through will do the same thing. An instant barrier like Zip-Wall is great, but you really need even less permeability in order to keep drywall dust out.
The other half to the equation is creating negative pressure. Setting up a box fan, with the air flowing outside, is enough to expel some drywall dust. Though it will not remove all dust, it will significantly cut down on the amount of dust clouding up the air.
Drywall Vacuum Sander
Another way to reduce (but not entirely remove) drywall dust, the drywall vacuum sander consists of a hose attached to your wet-dry shop vacuum. On one end is the sander, a special grid-like implement that sucks the drywall dust away and down through the hose. At the other end of the hose is a bucket of water.
Dusty air runs into the bucket, trapping the dust in the water.
It is an ingenious idea, except for one thing: it really does not work. The problem is that the suction on the sander head makes it very hard to move the sander on the wall.
However, the drywall vacuum sander will work in small areas. For example, you might have a joint or two that you need to sand down. But for an entire house—or even a room's worth—of drywall, it would significantly impede your progress.
Wet Sanding Drywall Joints
Wet drywall sanding is not really sanding. It means using a damp sponge to smear the hardened but water-soluble drywall joint compound away.
If you have ever wiped dried flour dough from a kitchen counter, it is much the same thing. Wet sanding works fine on a small scale—a joint or two—but impossible to do an entire room.