If you're not a fan of cigarettes, you probably hold your breath as you hurry past the smokers that hang out in front of office buildings, stores, and restaurants. Smokers are banished outside because a growing number of cities concerned with the possible health effects of secondhand smoke have banned smoking in eateries, workplaces and other such establishments. Turns out holding your breath might not be such a bad idea. Because scientists at the University of Georgia have found that sidewalk smokers can generate more pollution than passing cars. Athens, Georgia, is a major college town, and on the weekends, students are packed shoulder to shoulder outside bars and restaurants. And since smoking is banned inside such locations, plenty of those kids are puffing up a storm. That made the Georgia researchers wonder whether outdoor secondhand smoke could present a health hazard of its own. So they measured the carbon monoxide levels outside a handful of bars and restaurants. Because this gas is also found in car exhaust, the researchers counted the number of cars and the number of smokers. And they found that the pollution was coming from the people, not the tailpipes. So next time you stroll past a bunch of the banished, take a deep breath and feel free to run.