As luck would have it, the air quality sensors that University of Utah researcher Daniel Mendoza and his colleagues installed in Park City, Utah in September 2019, hoping to observe how pollution rose and fell through the ski season and the Sundance Film Festival, captured a far more impactful natural experiment: the COVID-19 pandemic.
Throughout the pandemic, the air sensors watched during lockdowns as air pollution fell in residential and commercial areas, and then as pollution rose again with reopenings. The changing levels, the researchers found, which behaved differently in residential and commercial parts of the city, show where pollution is coming from and how it might change in the future under different policies.
“The lockdown period demonstrated how low pollution levels can be and showed what the background pollution is in the area,” says Mendoza, a research assistant professor in the Department of Atmospheric Sciences and visiting assistant professor in the Department of City & Metropolitan Planning. “The very low levels of PM2.5 [fine particulate matter] can be considered an aspirational target and could spur increases in renewable and low-polluting energy sources.”
The study, supported by the Sustainability Office of Park City, is published in Environmental Research.
Before this study, neither Park City nor Summit County, Utah had a long-term record from regulatory air quality sensors. Although the population of Park City is much smaller than the Salt Lake Valley, its geography still creates temperature inversions that can trap and concentrate emissions from cars, businesses and other sources. Mendoza, who also holds appointments as an adjunct assistant professor in the Pulmonary Division at the School of Medicine and as a senior scientist at the NEXUS Institute, and his colleagues set up sensors at two different locations, one atop the building of the KPCW radio station, in Park City’s “Old Town” district, representing a bustling commercial area. The other was located at the Park City Municipal Athletic & Recreation Center, in an affluent residential area.