Inheriting a smoking tenant

[Louie E.]

Finally put my first property under contract!  Yay!  Financing should be good by next week.  Fingers crossed.

It is a 4-plex and I will be inheriting the tenants already in all units.  

An issue is that one tenant smokes in the unit that he is in.  What would be the best way to handle this if I do not want him to smoke in the unit?  I will have to stipulate this in the new lease contract.  But there would be no guarantee that he would abide.

Thanks