The Atlantic Cities runs a series of 1940s photos from the University of Pittsburgh's Smoke Central Lantern Slide Collection that show a smoky, sooty city devoted to coal.
In 1941, influenced by a similar policy introduced in St. Louis four years earlier, the city of Pittsburgh passed a law designed to reduce coal production in pursuit of cleaner air. Not willing to cripple such an important part of the local economy, it promised to clean the air by using treated local coal. The new policy ended up not being fully enacted until after World War II.
Original source: The Atlantic Cities
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