The Windy City is going the way of California, New York, Florida, Washington state (whose ban takes effect today), Boston, D.C., and various other jurisdictions too depressing to list. Bars don't have to ban smoking until June 30, 2008, after which they can theoretically apply for exemptions. A.P. reports that "owners would have to prove that their establishments feature air filtration or ventilation systems that render patrons' exposure to secondhand smoke equivalent to the exposure they would receive in the outdoor air around the establishment. The ordinance's sponsor, Ald. Ed Smith, said no such technology exists, and he doubts that it will be in place by the summer of 2008."