LOS ANGELES — It was a nightmare fire season that California won’t soon forget.
As more than 9,000 wildfires raged across the landscape, a canopy of smoke shrouded much of the state and drifted as far away as Boston.
All told, more than 4.3 million acres would be incinerated and more than 30 people killed. Economic losses would total more than $19 billion.
But the damage caused by California’s 2020 wildfire season is still coming into focus in some respects, particularly when it comes to the air pollution it generated.
In an analysis published this week in the annual Air Quality Life Index, researchers found that wildfire smoke likely offset decades of state and federal antipollution efforts, at least temporarily.
Even as the COVID-19 pandemic took cars off the road and temporarily halted some industries, particulate pollution — widely considered one of the greatest threats to life expectancy — spiked to some of the highest levels in decades in parts of California in 2020, according to the Energy Policy Institute at the University of Chicago, which produces the report estimating how air pollution may reduce life expectancy.
Nationally, 29 of the top 30 counties with the highest level of particulate pollution that year were in California, researchers found.
The report is the latest to highlight the dangerous health effects of wildfire smoke at a time when drought and climate change are fueling extreme wildfire behavior. Now, as the state enters what is expected to be another serious wildfire season, researchers say the toll these natural disasters can take on human health is striking.
“Places that are experiencing frequent or more frequent wildfires are going to experience higher air pollution levels, not just for a couple of days or weeks, but it could impact the annual level of exposure,” said Christa Hasenkopf, director of air quality programs at the University of Chicago institute. “It can bump up that average to unsafe and unhealthy levels that really do have an impact on people’s health. When we think of wildfires, we think of short-term events — and hopefully they are — but they can have long-term consequences (considering) your overall air pollution exposure.”
Mariposa County, a sparsely populated county seated in the western foothills of the Sierra Nevada, typically enjoys cleaner air than much of the state. But in 2020 it led the nation in annual average concentrations of fine particulate at 22.6 micrograms per cubic meter — more than four times the World Health Organization recommended guidelines. Likewise, more than half of all counties in California experienced their worst air pollution since satellite measurements began collecting data in 1998.