Somewhere in this great land of ours, we suppose, are men and women who stare at the gray-tinged photographs of the Beijing Olympics and think of what have might been.

What if that inversion layer hadn’t settled over Donora, Pa., that day in October 1948, creating a smog that killed 20 people? What if the United States hadn’t passed the Clean Air Act in 1970? What if the Nixon Administration hadn’t created the Environmental Protection Agency? What if the EPA had been neutered? What if Congress hadn’t kept piling on, strengthening the Clean Air Act in 1977 and 1990?

But no. The United States had to go and listen to the weak-kneed “environmentalists” who complained about a little “sulfur dioxide,” who whined about “heavy metals,” who griped about harmless little chemicals like “Toluene” and “trichloromethane.” So-called “scientists” and their “studies” came up with dubious “statistics” about the danger posed by “ozone” and “particulate matter.”

Titans of industry tried to warn us. They spent billions of dollars lobbying against this kind of regulation, telling us that environmental regulations would cost us jobs, pointing out that fancy-schmancy “scrubbers” on smokestacks and “catalytic converters” on cars would increase the cost of doing business, costing us jobs. The air wasn’t that bad, they said.

The Gipper knew. “Trees cause more pollution than automobiles,” President Ronald Reagan said in 1981. But nobody did anything about it until President George W. Bush came along 20 years later and allowed the timber industry to whack down more trees in the “Healthy Forests Initiative.”

The Gipper had it right in 1966: “A tree is a tree. How many more do you have to look at?” Now it’s Beijing that has the dirtiest air in the world, not Los Angeles or New York or Houston. And, no coincidence, it’s Beijing that has all the jobs. It’s the Chinese who know how to treat industry. It’s China that has all the colorful plumes of yellow and green and orange smoke making the skies so festive and bright.

Sure, the marathoners and bicyclists are worried about gagging during their races, but they need to listen to Arne Ljunqvist, a Swedish physician who is chairman of the International Olympic Committee’s medical commission. Last week, he noted the gray air in Beijing and said, “The mist in the air . . . that we see is not a feature of pollution primarily but a feature of evaporation and humidity.”

It’s not smog; it’s mist! It’s not pollution; it’s humidity! The U.S. Chamber of Commerce needs to hire this guy.