Question them is that because there is a State or Federal law banning smoking, or because the school/college/university/bar etc... have implemented their own ban?
It varies from state to state, and within states it varies from city to city. Here in Virginia restaurants and bars can technically still allow smoking, but the law says there has to be a non smoking section completely separated from the smoking section and with a separate ventilation system. Very few places meet that requirement.
I remember up until I was in third grade, teachers could smoke in the corridors. Then the local law changed and they could only smoke in the teacher's lounge. Years later in high school, they were banished to the parking lot. Now, as I understand it, they have to leave school grounds altogether to smoke. These were all city ordinances that came a year or two before similar state laws.