If you ever thought that the emergence of clean energy technology hasn’t helped to clean up our environment, think again. These photos of Pittsburgh in the 1940s show just how bad the air used to be, before we had regulations and cleaner energy technologies in place. Buildings in the city had to be steam-cleaned in order to get the sticky dirt off of them, so imagine what it was like to breathe the air there on a daily basis. The photos post-air quality regulations are amazing, as one can plainly see the difference that it makes.

There are many countries around the world just starting to fight their own battles with air pollution after years of ignoring it, and even some cities here in the U.S. are still trying to clean up years of lax air regulations. Los Angeles, for example, still tops the “most polluted” city list in America, but they have come a long way since the 1980s when residents couldn’t see the nearby mountains at all.

These images from Pittsburgh during the 1940s should serve as a reminder as to just how important it is that we continue to develop new ways of making clean energy. We’ve come a long way from those days, but we still have a ways to go.

[via Reddit]

Image Credit: Smoke Control Lantern Slide Collection, ca. 1940-1950, AIS.1978.22, Archives Service Center, University of Pittsburgh.