John e-mails Mr. Answer Person: "I have a question regarding smoking. Is it not illegal in Iowa to smoke on City Property. And doesn't the city technically own the streets from sidewalk to sidewalk. So aren't the people who stand in front of the business's downtown and smoke technically smoking on city property?"
Mr. Answer Person says: "I assume you're talking about the so-called Smoke-Free Air Act that was passed in 2008. That legislation bans smoking in "public places." But it defines "public places" as "an enclosed area to which the public is invited or in which the public is permitted, including…restaurants, bars, public and private educational facilities, health care provider locations and hotels and motels." Nowhere in the legislation are sidewalks mentioned. You could try to make the argument that sidewalks are "technically" city property, as you say, but I'm going to guess that the police will be less than enthusiastic about ticketing people who were kicked out of the bars and restaurants in the first place because they were smoking.
But if you're committed to this task, here's the state legislation: