Wildfire smoke deaths

Global study: Wildfire smoke kills people in cities far from fires

Guatemala, Thailand, and Paraguay had the highest proportion of estimated annual deaths from wildfire smoke.

Wildfire smoke causes more than 33,000 deaths a year across 43 countries, according to a new global study.


While previous studies estimated premature deaths from wildfires in a specific country or region, authors of a study published Wednesday in Lancet Planetary Health say this is the most comprehensive assessment to-date of global wildfire mortality. The findings come as the smoke from yet another season of record-breaking wildfires in the Northern Hemisphere impacts air quality hundreds of miles away from burn areas.

"Policy makers and public health professionals should raise awareness of wildfire pollution to guide prompt public responses and take actions to reduce exposure," write the study authors.

The study authors first estimated daily fine particulate matter (PM 2.5) concentration using a combination of machine learning, ground measurements, weather conditions, and chemical transport models. They then cross-referenced those pollution levels with data on more than 65 million deaths from 2000-2016 across 749 cities in 43 countries to get city-specific death estimates from wildfires.

They found that short-term exposure to wildfire PM 2.5 pollution caused, on average, 33,150 deaths a year in the countries looked at in the study, with an estimated 6,993 cardiovascular deaths and 3,503 respiratory-related deaths a year.

Of the countries studied, Guatemala had the highest proportion of estimated deaths from wildfire smoke, followed by Thailand and Paraguay. The authors note that all the mortality data used in the study comes from cities, and that the study is not a comprehensive look at global mortality; for example, although wildfires have burned more than 40 million acres in Siberia this summer, no Russian cities were included in the study.

Far-reaching impacts of wildfires

Lake Tahoe wildfire

Wildfire approaching South Lake Tahoe, September 1, 2021. (Credit: The National Guard/flickr)

Lead author Yuming Guo, professor of global environmental health and biostatistics at Monash University, told EHN that he was surprised to see that citizens from certain countries that don't have frequent wildfires, like France and Germany, were still harmed from wildfire smoke.

PM 2.5 refers to particles that are 2.5 microns or smaller in diameter—for reference, a human hair is about 70 microns wide. Because of their small size, these fine particles can travel deep into the lungs, where they can damage airways and enter the bloodstream. Children, infants, older adults and people who already have heart and lung conditions are especially at-risk from PM 2.5 pollution.

While wildfires are far from the only source of PM 2.5 pollution in cities, the study authors found that PM 2.5 exposure from wildfires was more deadly, and longer-lasting, than fine particle pollution from other urban sources. They suspect that's in part because of the chemical makeup and smaller size of the particles in wildfire smoke.

Wildfire smoke also contributes to suicide, diabetes, renal diseases, and other conditions, said Guo. The study authors suggest that future research should look at the mortality data by age, sex, and other factors to better understand who is most vulnerable.

Climate change is worsening wildfires by making wildfire-prone parts of the world, like California and Australia, hotter and drier.

Banner photo credit: Chris LeBoutillier/Unsplash

A group of white corals on a coral reef.

Record ocean heat drives catastrophic coral bleaching across 84% of reefs worldwide

A global coral bleaching event has now affected over four-fifths of the planet’s reefs, the most extensive damage ever recorded, as ocean temperatures remain historically high.

Isabella O’Malley reports for The Associated Press.

Keep reading...Show less
Sunrise in the woods

Get our Good News newsletter

Get the best positive, solutions-oriented stories we've seen on the intersection of our health and environment, FREE every Tuesday in your inbox. Subscribe here today. Keep the change tomorrow.

A $100 dollar bill encased in an ice block.

EPA chief Lee Zeldin defends freezing $20B in climate grants, citing alleged conflicts

U.S. Environmental Protection Agency Administrator Lee Zeldin on Monday defended his decision to halt $20 billion in climate funding, accusing media and courts of ignoring evidence of misconduct among grant recipients.

Jean Chemnick reports for E&E News.

Keep reading...Show less
A closeup of a white wind turbine against a blue sky.

Trump’s energy chief says clean energy credits waste taxpayer money and worsen the grid

Energy Secretary Chris Wright dismissed clean energy tax credits as ineffective and costly during an Earth Day interview, defending fossil fuels and calling global warming potentially beneficial.

Ashleigh Fields reports for The Hill.

Keep reading...Show less
Diverse group of young people in an auditorium.

Trump administration crackdown halts over 400 NSF research grants tied to equity and studies on misinformation

A wave of cancellations by the National Science Foundation (NSF) has ended hundreds of research grants, many focused on diversity and misinformation, amid a broader push by the Trump administration to reshape federal science funding.

Katrina Miller and Carl Zimmer report for The New York Times.

Keep reading...Show less
The torso of a judge in a black robe holding a gavel on a desk next to a red-covered book.

Judge's sanctions against Michael Mann revive battle over climate defamation case

A Washington, D.C., judge accused climate scientist Michael Mann and his legal team of misconduct during a defamation trial, reigniting a legal fight that has spanned over a decade.

DeSmog reports.

Keep reading...Show less
A neighborhood of burned homes destroyed by a wildfire with hills in background.

Climate disasters are driving up housing costs and displacing low-income residents

A surge in extreme weather events fueled by climate change is amplifying the global housing crisis, pushing prices higher and pushing vulnerable people out of their communities.

Dave Braneck reports for Deutsche Welle.

Keep reading...Show less
Utility towers and power lines stretching into the distance at sunset.
Credit: Joe/Pixabay

Utilities seek legal shield from wildfire lawsuits as climate risks grow

As utilities face growing wildfire liability tied to aging power lines and worsening climate conditions, lawmakers across the U.S. West are weighing whether to protect them from massive lawsuits or leave them on the hook.

Alex Brown reports for Stateline.

Keep reading...Show less
From our Newsroom
Regulators are underestimating health impacts from air pollution: Study

Regulators are underestimating health impacts from air pollution: Study

"The reality is, we are not exposed to one chemical at a time.”

Pennsylvania governor Josh Shapiro speaks with the state flag and American flag behind him.

Two years into his term, has Gov. Shapiro kept his promises to regulate Pennsylvania’s fracking industry?

A new report assesses the administration’s progress and makes new recommendations

silhouette of people holding hands by a lake at sunset

An open letter from EPA staff to the American public

“We cannot stand by and allow this to happen. We need to hold this administration accountable.”

wildfire retardants being sprayed by plane

New evidence links heavy metal pollution with wildfire retardants

“The chemical black box” that blankets wildfire-impacted areas is increasingly under scrutiny.

People  sitting in an outdoors table working on a big sign.

Op-ed: Why funding for the environmental justice movement must be anti-racist

We must prioritize minority-serving institutions, BIPOC-led organizations and researchers to lead environmental justice efforts.

joe biden

Biden finalizes long-awaited hydrogen tax credits ahead of Trump presidency

Responses to the new rules have been mixed, and environmental advocates worry that Trump could undermine them.

Stay informed: sign up for The Daily Climate newsletter
Top news on climate impacts, solutions, politics, drivers. Delivered to your inbox week days.