This is along the lines of prevention rather than treatment, but I found that when I stopped smoking, the permadust problem went away. For me.
With that, I determined that if I ever had a "$10 million" layout, it would have a viewing area with appropriate ventilation for them as smoked. Of course, it would also have continuous air filtration for the whole layout, anyway.
Dust never sleeps! Though it does seem to lie down a lot.