There’s a new movement in town that has almost no opponents, and it’s driving smokers from their beloved bars and into the streets. The movement’s newest convert is d.b.a.; the Frenchmen Street bar became smoke- free on January 3. Owner Tom Thayer timed the switch to coincide with the new year, when many smokers vow to cut back, and he hasn’t seen any drawbacks yet. “So far, so good,” he says. “I’d say 98 percent of customers are backing it.”

While the decision to go smoke-free doesn’t nec...