New Stanford-led study finds rising smoke exposure may drive a surge in premature deaths
-
Researchers estimate that between 20112020, wildfire smoke exposure contributed to about 41,380 extra deaths per year across the U.S.
-
Under a business-as-usual warming scenario, annual excess deaths from smoke could rise by more than 70%, to about 71,420 lives lost per year by 2050.
-
Even in a scenario where emissions are sharply reduced, smokerelated mortality would still remain high, and the economic damages alone from these deaths may exceed costs from all other climatedriven harms.
Its easy to think of wildfire smoke as nothing more than an irritant haze in the sky, the smell in your lungs. But a new study suggests it's doing something much more serious: quietly raising the U.S. death toll.
Researchers from Stanford University now estimate that, nationwide, exposure to smoke especially from wildfires has already been linked to tens of thousands of extra deaths annually. And with climate change intensifying fires, the problem is likely to get worse.
While previous research has explored how small particles in the air harm health, the unique mix of chemicals in wildfire smoke and its long reach, sometimes carried across states make this a special concern.
Theres a broad understanding that wildfire activity and wildfire smoke exposure are changing quickly. This is a lived experience, unfortunately, for folks on the West Coast over the last decade and folks on the East Coast in the last few years, senior study author Marshall Burke, said in a news release.
Our paper puts some numbers on what that change in exposure means for health outcomes, both now and in the future as the climate warms.
The study
To pin down how many deaths are tied to wildfire smoke (and what might happen in the future), the team combined multiple strands of data and statistical modeling. Heres how they approached it:
-
Historical death records & smoke measurements. The scientists gathered county-level data on all recorded deaths in the U.S. from 2006 to 2019. They also tracked ground-level smoke emissions, wind patterns, and how particulate matter moves through the air.
-
Machine learning & statistical links. They used machine learning models (alongside more traditional statistical methods) to link changes in smoke concentration with mortality. In other words: if smoke increased in a place, how did death rates respond?
-
Future projections under climate scenarios. Using global climate models, they projected how fire activity and smoke levels might change under different warming pathways. Then, they extended their mortality-smoke relationship forward into those futures, up through 2050.
They also allowed for the fact that health impacts of smoke might persist meaning that exposure in one year could lead to excess deaths up to three years later.
The results
Heres a look at the findings:
-
In the 20112020 period, wildfire smoke was estimated to cause 41,380 excess deaths per year across the U.S.
-
Under a high-warming business-as-usual scenario, that number could jump to 71,420 excess deaths annually by 2050 a ~73% increase.
-
Over the next three decades (20262055), the cumulative excess death toll could reach 1.9 million.
-
When converted into economic terms, the cost from smoke-driven deaths under warming may outstrip the projected costs from all other climate-related damages combined (storms, heat, agriculture, etc.).
-
Perhaps surprisingly, even with aggressive emissions reductions, the researchers expect smoke-related mortality to stay high likely still exceeding 60,000 deaths per year by 2050.
On a state-by-state level, the biggest projected increases (beyond baseline) are in California ( 5,060 additional deaths), New York ( 1,810), Washington ( 1,730), Texas ( 1,700), and Pennsylvania ( 1,600).
Our understanding of who is vulnerable to this exposure is much broader than we thought, Burke said. Its pregnant people, its kids in schools, its anyone with asthma, its people with cancer. We look at one specific health outcome in this study mortality and unfortunately find a shared burden of exposure for individuals across the U.S.
Posted: 2025-09-25 17:58:56
