US counties reporting good air quality days

American counties posting cleaner air days and the UFC scheduling more events per year. The fighters are not, on average, breathing the cleanest air. The clean-air counties are not, on the whole, hosting Octagon nights. The graph remains tactful.

UFC events per year climbed from about 20 in 2005 to over 40 by 2022 as the promotion expanded internationally and the post-Reebok-deal calendar densified. US counties reporting good air quality days expanded across the same window thanks to Clean Air Act enforcement, the long retreat of coal-fired power, and reduced industrial emissions. Two independently improving metrics in two independent industries, sharing a decade because both happened to improve through the 2010s. The country fought more often and breathed better.

Some metrics simply got better in parallel. Combat sport and lung health, both up.