January 6, 2022 4:00 pm
Large wildfires and severe heat events are happening more often at the same time, worsening air pollution across the western United States, a study has found. In 2020, more than 68% of the western U.S. — representing about 43 million people — were affected in one day by the resulting harmful-levels of air pollution, the highest number in 20 years. The study found that these concurrent air pollution events are increasing not only in frequency but duration and geographic extent across the region. They have become so bad that they have reversed many gains of the Clean Air Act. The conditions that create these episodes are also expected to continue to increase, along with their threats to human health.