Wildfires are undoing years of progress cutting man-made air pollution and are likely to become an even larger polluter in the future, a Stanford University study found. Though the findings apply across the U.S., the phenomena is particularly dramatic in California and Nevada: Particulate pollution fell 32% from 2000 to 2015 in those states, then jumped 14% from 2016 to 2022. Experts blamed climate change and years of forest mismanagement for the increasing frequency and intensity of the blazes.