Researchers at the University of Utah are studying how air pollution changed throughout the pandemic in Park City.
Air quality sensors were originally installed in November and December 2019 to track how pollution fell and rose during ski season; but then the pandemic hit, changing the nature of the study.
This allowed for a natural experiment to occur.
During the initial pandemic lockdown in March 2020, air pollution levels fell across the board as restaurants shut down and people stayed in their homes. But as businesses started to reopen six weeks later, pollution started to rise again.
Researchers also found pollution levels changed in different areas of the city, shifting from commercial to residential zones.