(STACKER) – “The Crown” episode “Act of God” recreated for viewers the Great Smog of London, a catastrophic fog of polluted air that settled over the city in the winter of 1952. Sometimes called the Big Smoke, a dense cloud of coal-choked air turned day to night and killed thousands. An almost identical event had already occurred in 1948, in Donora, Pennsylvania. Home to the Donora Zinc Works, Donora was consumed by a dense smog filled with airborne pollutants released during zinc smelting. When the same unusual weather patterns that caused the disaster in Donora materialized in London, scientists knew what was coming but it was too late to act.

Following other tragedies in New York and the smoggiest day on record in Los Angeles, the U.S. government passed the Air Pollution Control Act of 1955—the predecessor of the Clean Air Acts. Nixon’s administration established the Environmental Protection Agency in 1970 with the mission of enforcing regulations, collaborating with other organizations and sponsors, and educating the public about the hazards of pollution. The EPA has been successful in improving air quality in places like Donora.

Burning fossil fuels is the primary cause of both air pollution and climate change. In 2022, wildfires in the West—most of which were human-caused—were also culprits in the most polluted areas. Stacker compiled a list of the metro areas with the worst air pollution in the U.S. using the 2022 American Lung Association’s State of the Air Report.

25 (tie). Augusta, Georgia

25 (tie). Shreveport, Louisiana

24. St. Louis

22 (tie). Chicago

22 (tie). Houston

21. Yakima, Washington

18 (tie). McAllen, Texas

18 (tie). Philadelphia

18 (tie). Eugene, Oregon

16 (tie). Detroit

16 (tie). Redding, California

15. Bend, Oregon

14. Pittsburgh

13. Indianapolis

12. Cincinnati

11. Sacramento, California

10. El Centro, California

9. Chico, California

#8. Phoenix

7. Fairbanks, Alaska

6. Medford, Oregon

5. Los Angeles

4. San Jose, California

2 (tie). Fresno, California

2 (tie). Visalia, California

1. Bakersfield, California