Restaurant sells actually increase when they go non smoking. No one wants to go to a restaurant/bar and smell like an ashtray after they leave. It is simple...If you have a habit that harms others, do that habit on your own property. If a restaurant/bar owner wants to be open to the public, then he/she has certain responsibilities to make sure that his establishment is safe for the public. That includes safety of the food/drink, adequate fire exits, and yes air quality.