What is this stuff and why does it keep coming back?

there's a fine layer of like soft fluffy sand on all of my furniture, i wipe it away but it keeps coming back, even with all of my windows closed for a week, and if i leave it it gets thicker and thicker, i think its on my couch too, when i hit the cushion i see a little cloud of it poof into the air and then float to the ground, its almost like ash, but different, and i don't have a fireplace or smoke inside, what is this stuff? how do i get rid of it?