"Over the last few decades, air in the U.S. has undergone a remarkable transformation: pollution levels of health-damaging tiny particles have dropped by roughly 40% since 2000, primarily thanks to the country's decades-long effort to improve air quality through the Clean Air Act, a landmark environmental law.
Smoke from wildfires fueled by human-driven climate change, however, has erased roughly 25% of those air quality gains, according to a new study published Wednesday in Nature. "We've seen really remarkable improvements in air quality," says Marissa Childs, one of the authors of the study and a researcher at Harvard's Center for the Environment. "But wildfire smoke is undoing that progress in many states."
The effects are more pronounced in Western states, where smoke-laden days have become an annual fact of life. Schools keep kids inside during recess; emergency rooms know to prepare when wildfires break out nearby. The study found that since 2016, in states like California, Washington and Oregon, wildfire smoke has added enough pollution to the air to wipe out nearly half of the total air quality gains made from 2000 onward."