The reason the surgeon general warns against smoking is that the smoke contains tars and poisonous, staining liquids that get into pores of the lungs, as smoke does to paper, so you need to get smoke out of walls, which is hard to do. It doesn't stay on top, like dust.
You can cover it up by various means, but some will stay there, as it does in the body to contribute to the 50-year-old's afflictions.