Wildland fires estimated to release more organic air pollutants

by Clarence Oxford
Los Angeles CA (SPX) Dec 30, 2025

Wildland fires that burn forests, grasslands and peat may release more airborne organic compounds than previously recognized, according to a new analysis of emissions from 1997 to 2023. Researchers report that when a wider range of organic gases is considered, fires contribute substantially to air pollution and interact with emissions from human activities in several global hotspots.

The study, published in Environmental Science and Technology, focuses on volatile organic compounds (VOCs) and on intermediate- and semi-volatile organic compounds (IVOCs and SVOCs), which more readily form fine particulate matter that can harm human health when inhaled. Many earlier inventories emphasized VOCs and largely omitted IVOCs and SVOCs because their numbers are large and measurements are difficult, leading to potential underestimates of fire-related pollution.

Lead author Lyuyin Huang reports that incorporating these additional organic gases raises estimated global wildland fire emissions of organic compounds by about 21 percent compared with previous assessments. Huang describes the updated global inventory as a basis for more detailed air-quality modeling, health risk assessment and climate policy analysis linked to wildland fire smoke.

The team, led by Shuxiao Wang, accessed a database of burned land area for global forest, grass and peatland wildland fires from 1997 to 2023, then combined these data with emission measurements of VOCs, IVOCs, SVOCs and extremely low volatility organic compounds for each vegetation type. For vegetation types without field measurements, the researchers used laboratory experiments to predict the mix of organic compounds released, then calculated annual emissions around the world.

Their calculations indicate that wildland fires emitted an average of 143 million tons of airborne organic compounds per year over the study period, with the inclusion of IVOCs and SVOCs accounting for the 21 percent increase over past estimates. The results suggest that these partially volatile compounds from fires may play a larger role in fine particle formation and air quality than earlier inventories implied.

When the researchers compared this new wildland fire inventory with a previous estimate of organic emissions from human activities, they concluded that human sources still dominate total organic gas emissions globally. However, fires and human activities release comparable amounts of IVOCs and SVOCs, indicating that both sectors are important contributors to the components that efficiently generate fine particulate pollution.

The analysis also highlights regions where emissions from wildland fires and human activities overlap, including Equatorial Asia, Northern Hemisphere Africa and Southeast Asia. The authors say these emission hotspots face complex air-quality challenges that require strategies targeting both fire management and anthropogenic sources to reduce exposure to harmful pollutants.

The work received support from the National Natural Science Foundation of China, the National Key R and D Program of China, the Samsung Advanced Institute of Technology and the Center of High Performance Computing at Tsinghua University. The article Global Wildland Fire Emissions of Full-Volatility Organic Compounds from 1997 to 2023 was published in Environmental Science and Technology on December 29, 2025.

Research Report:Global Wildland Fire Emissions of Full-Volatility Organic Compounds from 1997 to 2023