Add more ammunition to the arsenal of anti-smoking efforts with the latest report on secondhand smoke from the Centers for Disease Control and Prevention.

According to researchers, more than 1 in 5 high school and middle school students are passengers in cars while others are smoking.

The study, based on national surveys in schools, and released by the CDC on the Internet Feb. 6, reports that more than 22 percent of teens and preteens were exposed to secondhand smoke in cars in 2009.

People quit smoking for all sorts of reasons, most often because of health concerns, either their own or those of loved ones. Smokers know their habit isn’t healthy.

But outlawing a legal activity isn’t as much of a deterrent as some might like to believe.

It just turns ordinary citizens into pariahs, “socially unacceptable” and condemned for their habit while others practice their own distasteful – and potentially dangerous – habits without the scorn of friends, family and even strangers.

Ever overhear a stranger ask an overweight person why his or her lunch choice is a supersized burger and fries? Probably not, especially with so many people carrying concealed these days. But criticizing a smoker and with marked disdain and self-righteousness? It’s the in thing to do.

A parent who smokes with children in the car, according to current evidence, is jeopardizing the children’s health. Why would a parent who is normally sometimes overly concerned about the sniffles not understand the danger? Thus the CDC study is properly advising against the practice. The study authors, with all good intentions, have encouraged all states to follow the lead of a few that have banned smoking in a vehicle when a child is present.

Attempts at prohibition didn’t work with alcohol. And let’s be honest: It hasn’t worked with drugs. Why would we expect it to work with tobacco?

Education would be a more worthy effort, if we spent as much time – and funding – on discussion as we spend trying to dictate individual behavior.