The Clean Air Act, the sweeping federal law designed to control air pollution, has been celebrated for saving millions of human lives since it was first enacted in 1963 and expanded four more times. Its checks on industrial and tailpipe pollutants are expected to prevent more than 230,000 deaths in 2020 alone, along with millions of asthma attacks and thousands of ER visits during a year of a raging pandemic. But people were not the only ones to benefit from the act. A recent study led by the Cornell Lab of Ornithology finds that that the policy, designed to protect human health, has also saved as many as 1.5 billion birds in the past 40 years. That’s about 20 percent of the total estimated North American bird population. "It is the first study that quantifies how changes in air pollution in the United States—or really anywhere—impacts birds over such a large area," says Tracey Holloway, an atmospheric scientist at the University of Wisconsin-Madison who wasn't involved...