SALT LAKE CITY — Cutting pollution that is harmful to human health is not only helping people but is helping migratory bird populations in a staggering way.

A new study by Cornell University and the University of Oregon suggests that efforts under the Clean Air Act to cut ozone pollution over the last 40 years may have averted the deaths of 1.5 billion birds, or 20% of bird life in the United States today.

Ground-level ozone is a vexing problem in Utah during the summer and the target of local research and regulatory efforts to tamp it down. Unhealthy ozone concentrations have even shown up in unlikely places like the mountainous region in Summit County.

Dave Livermore, the Utah state director of The Nature Conservancy, said the latest research demonstrates why it is critical to continue to cut emissions.

“The results of this study are very encouraging and show the clear link between human health and the health of our natural world,” he said. “We all benefit from clean air and clean water, and so do the wildlife resources which make so Utah special.”

A goose eats at Liberty Park in Salt Lake City on Wednesday, Nov. 25, 2020. | Kristin Murphy, Deseret News

The probe examined the relationship between bird abundance and air pollution using modeling that combined bird observations from the Cornell Lab of Ornithology’s eBird program with ground-level pollution data and existing regulations. 

Researchers tracked monthly changes in bird abundance, air quality and regulation status for 3,214 U.S. counties over a span of 15 years.

Specifically, the study looked at the effectiveness of the U.S. Environmental Protection Agency’s regulation of ground-level ozone and regulatory steps that have been taken to reduce summertime emissions of “precursors” that cause it form.

“Our research shows that the benefits of environmental regulation have likely been underestimated,” said co-lead author Ivan Rudi, an assistant professor in applied economics and management at Cornell in a posting on the Cornell Chronicle.

“Reducing pollution has positive impacts in unexpected places and provides an additional policy lever for conservation efforts.”

Study results suggest ozone impacts migratory bird populations directly by affecting their respiratory system — just like humans — and indirectly by affecting natural food supplies.

“Environmental policies nominally aimed at humans can also provide substantial benefits to other species,” a synopsis of the study said.

Ann Neville, the Northern Mountains regional director for The Nature Conservancy, echoed that sentiment.

“I think it is just another indicator how closely our environment and human health are related,” she said, noting that people have used birds historically as human health indicators — such as the canary in the coal mine.

“If these small migratory birds are not doing well, it is not going to be good for humans either,” she said. “Our Clean Air Act and Clean Water Act are helping these birds, but we want to be even cleaner because it affects humans. too. We need to find a balance so we can share the planet with all these wonderful animals.”