Like a smelly old butt being unceremoniously snuffed out, the habit of smoking is headed for the trash can of history. On Jan. 1 Pittsburgh International Airport will become only the latest example.

The Allegheny County Airport Authority has approved a new policy that bans all smoking at the facility, with the only exception being outside the Landside Building, but even there smokers won't find a hospitable refuge -- they will be kept at least 15 feet from the entrances.

No more will smokers be able to puff away in the airport's bars and restaurants, as they have since the airport opened 14 years ago. It is a welcome change for the cause of public health and the ease and comfort of the majority of people.

The new policy is stricter than Allegheny County's ordinance that permits smoking in bars where food service sales are 10 percent or less of revenues and that have fewer than 10 employees. Part of the reason is that many of the airport's bars and restaurants share the same owners, and the greater volume of food sales and number of employees do not trigger the usual exemptions.

Technicalities aside, this is enlightened public policy, in tune with national trends. Plenty of airports across the nation are smoke-free -- Los Angeles, Philadelphia, Chicago, Denver, to name some -- and everywhere the move is to be proactive to protect the health of workers and travelers.

Bars and restaurants are unlikely to be hurt because the ban will be uniform and people in transit can't very well leave the airport. Moreover, banning smoking in the airport is merely a continuation of what happens in the sky.

In short, only the most desperate, hard-core smokers will be inconvenienced. And if someone has to calm his nerves by grabbing a cigarette on the ground, it is surely time for him to quit.

With the surgeon general of the United States having warned of the pernicious effects of secondhand smoke, the debate about smoking has shifted. Although some state and local politicians have been slow to realize it, no responsible official body can afford to turn a blind eye to smoking.

Smokers are not being made into second-class citizens -- they can always smoke at home. It is letting smokers do their thing in public that makes second-class citizens of the rest of us who must breathe their poisons. Kudos to the airport authority for standing up for the real public interest.