3 days ago I had to take my 2 week old into the doctors because she was covered in a rash and I…

3 days ago I had to take my 2 week old into the doctors because she was covered in a rash and I didn't know what it was from I hadn't used anything new on her. So as a precaution now me and my fiancé don't want anyone smoking or coming near her right after they smoke. And my MIL just doesn't care about it and she keeps doing it. My little girl keeps smelling like smoke and I don't want to be disrespectful but what should we do about it?