Then the same should apply to him.As long as it is not in an environment where you would normally expect to risk finding one next door.
After all what is good for the Goose is good for the Gander.
A smoker moving into a previously smoke free environment and polluting it should be regulated by the apartment complex....not the government and the tenant inconvenienced should be well with-in their rights to request he relocate or the apartments accommodate the nonsmoker by moving them.