Denver bolted Saturday afternoon to the top of a foul list, No. 1 in air pollution among major cities of the world.
The city took first place with an air quality index ranking of 162, edging out Johannesburg, South Africa, which had a 160 ranking, according to IQAir, world air quality rankings.
Salt Lake City is No. 5 on the list Saturday afternoon with a 155 ranking. Both western U.S. cities are being overrun with smoke from distant California and West Coast wildfires because of atmospheric conditions and weather patterns.