My first reason to back this issue up is since 1964 approximately 2,500,000 non smokers have died from health problems caused by exposure to second hand smoke, so that means other employees who are non-smokers have to suffer. There are also many other health problems caused by second hand smoke such as; heart disease, lung cancer and strokes.
Secondly, it looks unprofessional for the business, you have people dressed professionally working for you, which means they are presenting your business/company, do you really want people