Increasingly wild veld fires in the western US are taking a devastating toll on the region’s air quality, and veld fire smoke is now half of the air pollution during the worst veld fire years, according to a new study.
Scientists from Stanford University and UC San Diego have found that toxic plumes of smoke, which can hide Western states for weeks if wildfires rage, are reversing decades of gains in reducing air pollution. Although heat-related deaths have previously been predicted as the worst consequence of the climate crisis, researchers say that air pollution caused by smoke can be just as deadly.
“For many people in this country, wildfires are going to be the way they experience climate change,” said Marshall Burke, an associate professor of earth science at Stanford and one of the study’s authors. “The contribution of veld fires to poor air quality has roughly doubled in the west over the past 15 years.”
Air pollution by fine particles, known as PM2.5s, has taken four months off the average American’s lifespan. And health researchers have only just begun to understand the disturbing health consequences that increased smoking exposure to broad sections of the U.S. population has added.
Wildfire seasons have become increasingly brutal in the American west, exacerbated by the climate crisis. The 2020 firestorms were among the worst in history, with 31 people killed, 10,000 buildings destroyed or damaged and more than 4 million acres burned in California alone. Huge parts of Colorado, New Mexico and Arizona were also scorched.
After California residents endured a month of orange-brown air full of dangerous small particles, another set of Stanford researchers followed dramatic increases in hospitalizations for things like strokes, heart attacks and asthma.
Bibek Paudel, a postdoctoral researcher at Stanford’s asthma clinic, found that hospitalizations for strokes and related conditions increased by 60% in the five weeks after fires began to smoke in Northern California last August due to lightning strikes. The number of pregnancies lost also doubled in the weeks after the fires – a surprising finding that researchers are still interpreting. Paudel also found significant increases in heart attacks and hospitalization by adolescents due to respiratory diseases.
“I do not think people are aware of the long-term health consequences of wildfire smoking,” said Mary Prunicki, director of research at the Sean N Parker Center for Allergy and Asthma Research at Stanford.
For decades, air quality in the U.S. has been improving due to the reduction of pollution by cars and factories, as mandated by the Clean Air Act. But over the past 40 years, the amount of land burned in wildfires has tripled, Burke’s study found.
The study, published in the Proceedings of the National Academy of Sciences, combined data from satellite images of smoke plumes combined with measurements obtained from air monitors on the ground, which record local air pollution, to model the total smoke exposure. The study consisted of all states west of (and including) New Mexico, Colorado, Wyoming, and Montana.
Smoke plumes can be detected using satellite images as they travel across the country. But it is difficult to say whether it is low enough to affect the air quality on the ground, and therefore the study created statistical models on how pollution changed to fire events at specific locations, combining information from satellites, air monitors and data models.
“Everyone knows that wildfires produce dirty air – so it’s no surprise,” Burke said. ‘What we could do in this study is to determine how big the contribution is. And we have found that it reverses much of the progress that has been made across the country in improving air quality. ”
Surprisingly, the study found that veld fire smoke spreads the effects of air pollution to whiter and richer populations. Historically, low-income communities have been hit hardest by air pollution, often because their homes are closest to highways and factories. But smoke spreads pollutants over much wider areas. Burke said the western U.S., where most wildfires occur, is also whiter and richer than other regions of the country.
As the plumes move through the land, the pollution can harm even people who live far from the fires, in the Middle East or the East.
“Field smoke is a nuisance that is much more equal than other pollution,” Burke said.
However, other research has shown that low-income populations can be hit harder if smoking in a region is blankets, because their smaller and older homes offer less protection.
Ironically, one of the future solutions to all this smoke may be to light more fires.
The increase in veld fires is partly due to warmer temperatures and drier conditions, but there is a growing consensus that this is also the result of the country’s policy of suppressing fires, instead of burning soil occasionally.
“There’s a lot of fuel on the ground,” Burke said. “Climate change dries it out and makes it much more flammable.”
Burke said a policy of using prescribed burns, which involves carefully controlling fires to clean the brush, could be an important strategy to reduce wildfires and reduce dangerous smoke exposures in the coming year.
“The benefits can be quite large, but there are a number of key questions that need to be studied,” he said.
“Otherwise, a year like 2020, which has historically been off the map, could be much more of the norm,” he said. “It’s awful to think about.”