Three decades ago, Surgeon General C. Everett Koop awakened Americans to the dangers of all that smoke drifting around the office, the airline cabin, the car, the restaurant. Those thin but low clouds weren't just annoying because they made your clothes and skin reek. Secondhand smoke, Koop explained, could sicken or kill:

"It is now clear that disease risk due to the inhalation of tobacco smoke is not limited to the individual who is smoking, but can extend to those who inhale tobacco smoke emitted into the air," Koop reported. Many smokers scoffed. Many people who lived and worked with them didn't know whether to invoke Koop's warning or ignore it and hope for the best.

Flash forward to 2015 : Offices are smoke-free. So are bars and restaurants and parks. Not as many kids grow up in homes with parents who smoke there. Guests don't plop down on the sofa and reflexively ask, "Mind if I smoke?" They know the answer. Ashtrays have all but vanished.

Those of us enjoying every lungful of clean air may forget, however, that many Americans still suffer serious health hazards of secondhand smoke. A new and startling statistic from the Centers for Disease Control and Prevention: Some 58 million Americans — 1 in 4 nonsmokers — are still exposed to secondhand smoke. Many of these are children, particularly African-American children.

We expect to learn in the future, as more Americans wise up and stop smoking, that fewer people will be sickened or die from secondhand smoke. For now, however, this is a continuing public health crisis that still demands attention, decades after scientists aired out the dangers of cigarette smoking.

Smokers know they're killing themselves with every puff. They can't or won't stop. But let's not forget those who have no choice but to suffer the consequences.

FROM AN EDITORIAL IN THE CHICAGO TRIBUNE