Wildfires and controlled burns worldwide may be pumping out far more air-polluting compounds than earlier calculations suggested, according to new research that accounts for overlooked emissions.
A study published Monday in the ACS journal Environmental Science & Technology estimates that wildfires and prescribed burns released an average of 143 million tons of airborne organic compounds each year from 1997 to 2023 — about 21% higher than previous assessments.
The findings suggest current air-quality models may be systematically underestimating health and climate risks associated with large-scale fires.
“Our new estimates increase the organic compound emissions from wildland fires by about 21%,” said first author Lyuyin Huang, according to ACS. “The inventory provides a foundation for more detailed air-quality modeling, health-risk assessment and climate-related policy analysis.”
The research, led by Shuxiao Wang, incorporated volatile organic compounds, or VOCs, along with intermediate- and semi-volatile types known as IVOCs and SVOCs. These latter compounds, which evaporate into gases at higher temperatures, more readily form fine particles in the air that can harm health if inhaled.
Most prior studies have ignored IVOCs and SVOCs because their vast numbers make them difficult to track, the American Chemical Society said in a press release.
To compile the data, the team drew from a global database of burned areas in forests, grasslands, and peatlands over the 26-year span. They paired it with emission details for each vegetation type, using laboratory tests to fill gaps where field measurements were unavailable.
While human sources overall outpace fires in organic emissions, the two contribute similar levels of IVOCs and SVOCs. Overlapping hotspots include Equatorial Asia, Northern Hemisphere Africa, and Southeast Asia, where managing air quality could prove especially tricky.
Separate research has tied wildfire smoke to more severe COVID-19 outcomes, respiratory and heart issues, and impaired learning and memory in children. The findings come amid events like the major blazes that scorched parts of the Los Angeles area earlier in 2025.
