America's Coming Smoke Epidemic

Summary

For 49 straight days, everyone in Seeley Lake was breathing smoke. A wildfire had ignited outside the small rural community in Montana, and the plume of smoke had parked itself over the houses. Air quality plummeted. At several moments, the concentration of particulate matter in the air exceeded the upper limit of what monitors could measure.Christopher Migliaccio, an associate professor of immunology at the University of Montana, saw an opportunity to do what few have ever done: study what happens after people get exposed to wildfire smoke. He and his team quickly cobbled together funding and drove out to Seeley Lake to get data.That was in 2017. The researchers followed up with residents for two years after the fires, checking on their lung function. To their surprise, the worst effects didn’t show up immediately, despite the heavy dose of smoke. Instead, people’s lung function seemed to deteriorate later. Right after the fires, about 10 percent of the cohort had lung function that fell below the lower limit of normal. By the one-year mark, about 46 percent did. At the two-year mark, most of those people still had abnormally poor lung function. “We were very surprised,” Migliaccio told me. He and his colleagues had intended to follow the residents for a third year, but then COVID hit. Instead, they tried exposing mice to wildfire smoke in a controlled lab environment. Their results pointed to a similar outcome: The worst effects took time to present.Migliaccio’s work can speak to only a single smoke event. But it is the type of event that more people in the United States are dealing with, over and over again. Until recently, wildfires that exposed large populations to smoke were a relatively rare occurrence. But that’s changing: More frequent and intense wildfires are erasing or even reversing decades of gains made in American air quality in the majority of U.S. states. Across the country, from 2012 to 2022, the number of people exposed to unhealthy air from wildf...