If the Clean Air Act had never passed, the smog in New York City might look a little more like Beijing or New Delhi on a bad day. In the early 1970s—just after the law was signed—it wasn't uncommon for the Manhattan skyline to be shrouded in clouds of pollution.
A new project superimposes Chinese pollution on modern U.S. cities, in an attempt (with a major caveat) to imagine how filthy the air would be without the Clean Air Act.
The caveat is that this is more fun than science. The designers, from an electricity company called SaveOnEnergy, didn't actually try to calculate how much pollution would be different in each city. Instead, they took data from one of the most polluted cities in the world—Xingtai, China—and tried to adjust it based on the population of cities in the U.S.
There are some problems with this. Air pollution, especially the particulate matter that makes up smog, has dropped a dramatic 80% in the U.S. since the Clean Air Act went into effect, but the law isn't the only reason. One economist calculated that it actually played a relatively minor role. (When U.S. manufacturing moved to China, for example, so did some of our pollution.) The images don't consider where power plants are, or how local industry changed as a result of regulation, or how much sprawl and traffic have affected current pollution.
Still, it's fascinating to imagine daily life in Chicago or Dallas if either had to deal with Xingtai's smog problem. It's not a pretty sight.
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