I have a black computer table, when I dust with a damp cloth, the dust appears a few hours later. However, when I use my vacuum cleaner with brush attachment, the table stays dust free for at least a day. I think sometimes when we dust, we just shift it around rather than remove it. Yes, half that dust is coming from you, in the form of shedded skin cells - and not from your "butt". The human body is quite capable of dealing with a little daily consumption of dust, mites, eggs etc.,
Please stop worrying about dust. This is not a healthy way of thinking.