Atlanta ? New research shows that smoking bans spare many children with asthma from being hospitalized, a finding that suggests smoke-free laws have even greater health benefits than previously believed.

Other studies have charted the decline in adult heart attack rates after smoking bans were adopted. The new study, conducted in Scotland, looked at asthma-related hospitalizations of kids, which fell 13 percent a year after smoking was barred in 2006 from workplaces and public buildings, including bars and restaurants.

Earlier U.S. studies, in Arizona and Kentucky, reached similar conclusions. But this was the largest study of its kind — and offered the strongest case that smoking bans can bring immediate health improvements for many people. The study appears in today’s New England Journal of Medicine.

Smoking bans have become increasingly common in the United States, where 35 states and the District of Columbia have laws that bar smoking in workplaces or restaurants and bars, or both. And more than 3,100 cities and towns have their own restrictions, according to the American Nonsmokers’ Rights Foundation.