Apparently one of the unforeseen but happy consequences of smoking bans is that they help discourage many teens from ever taking up the habit.

A new study from the Boston University School of Public Health has found that youths who live in communities with strict bans are 40 percent less likely to become regular smokers than those in communities with no bans or weak ones. Washington’s statewide ban, enacted in 2004 by voter initiative, prohibits smoking in public places as well as in bars and restaurants.

The study’s lead author said that bans reinforce the idea that smoking isn’t socially acceptable. In communities without bans or with weak ones, teens see smoking as the norm, not an ostracized activity.

Other benefits of smoking bans are widely known: Lower absentee rates among workers, fewer diseases and deaths associated with secondhand smoke, lower maintenance costs for businesses, and reductions in the number of heart attacks and strokes. But serving as a deterrent to youthful smoking has to be one of the best.

That’s because almost all addicted smokers began before the age of 18. Even the cigarette manufacturers’ own research shows that if people don’t start smoking by age 18, chances are they never will. And if they do start smoking at a later age, it will be easier for them to quit.

It all boils down to brain chemistry. Because teenagers’ brains are still developing, it’s easier for them to become quickly addicted to nicotine. That also makes them more susceptible to other, even more serious addictions later in life.

Even though this state’s smoking ban is likely to deter many teens from getting addicted to nicotine, it’s not a magic bullet. Too many teens are still lighting up, getting addicted, endangering their health and likely shortening their lives. Still, it’s welcome news that the voter-approved smoking ban is likely to have such an unexpected side effect.