I get what you describe, grey dust bunnies, quickly accumulating within a week after cleaning the floor under my bed. Because it is only around my bed that I see those, I assumed it was coming from my bed clothes, the blankets in particular. idk what the material is called, but generally when new it's described as "scratchy" by children, probably wool or polyester. Shaking these outside produces a lot of junk flying off. But the dust that I see accumulate elsewhere and floating through the air turns the off-white base-boards a sickly dark yellow, and the dust is black on a paper towel when wiped. Maybe wash your bed clothes and rinse thoroughly, and skip the dryer sheet. I've found too much detergent drys or sticks on clothes and produces a puff of particles when I take off my socks too quickly, in particular.