As record wildfires raged in areas around the world this summer—from Greece to Canada to Hawaii—California’s consistent exposure to wildfire smoke is proving its deadly toll. AQLI’s most recent report shows that out of the top 30 most polluted U.S. counties, 20 of them were in California in 2021—a year in which California experienced its second worst wildfire season in terms of acreage burned and its largest single wildfire.
Residents of California’s Central Valley are now consistently exposed to average particulate pollution (PM2.5) levels above both the WHO guideline and the nation’s own air quality standard. The most polluted county in California in 2021 was Plumas County, one of the counties that experienced the Dixie fire—the largest single wildfire recorded in California’s history. During that year, average pollution shot up to 26.6 μg/m3. The most polluted area of the United States in 2021, residents in Plumas would gain 2.1 years of life expectancy if the region met the WHO guideline. This was the first time in at least the last two decades that Plumas was more polluted than California’s Fresno county—which often experiences high industrial pollution—underscoring the heavy toll of the wildfires as well as the impact pollution policies have had in reducing traditional pollution sources.
As the planet becomes hotter, drier soil and drought conditions expose more areas to wildfire risks. As this past wildfire season proved, California is not the only home to rampant wildfires. They have run rampant in regions throughout the world, from Canada and Greece to Indonesia and the Congo Basin. Each wildfire brings a a surge in PM2.5 levels, exposing the communities near them to harm. Given the role climate change will play in exacerbating air pollution, with an increase in extreme wildfires being a poignant example, it is imperative that policies continue to be introduced to reduce the burning of fossil fuels.