Wildfire Smoke Is Erasing Progress on Clean Air

Smoke from wildfires has worsened over the past decade, potentially reversing decades of improvements in Western air quality made under the Clean Air Act, according to research published Thursday from Stanford University.

The new analysis reveals a picture of daily exposure to wildfire smoke in better geographic detail than ever before. Researchers found a 27-fold increase over the past decade in the number of people experiencing an “extreme smoke day,” which is defined as air quality deemed unhealthy for all age groups. In 2020 alone, nearly 25 million people across the contiguous...