UNC Researchers Receive Best Paper Award for Breakthrough Study on African Biomass Smoke
The research team recreated smoldering fires typical of sub-Saharan Africa in a large environmental chamber, burning fuels such as hardwoods, savanna grasses, leaves and cow dung to closely track how brown carbon particles form, what they are made of at the molecular level, how strongly they absorb light and how their properties change as smoke ages in the atmosphere.
January 8, 2026 I By Dave DeFusco
A study on a major but often overlooked driver of air pollution and climate change from Sub-Saharan African biomass combustion by researchers in the UNC Department of Chemistry and Gillings School of Global Public Health has been selected as one of Environmental Science &Technology’s (ES&T) 2024 Best Paper Awards.
The 2024 ES&T Best Paper Award recognizes studies that push boundaries and offer pathways toward cleaner air, a safer environment and a more sustainable future. With contributions from chemists, atmospheric scientists and public-health experts, the UNC-led study is a model of cross-disciplinary research designed to serve the public good.
“It’s an honor to have our work selected as one of the best papers of 2024,” said Jason Surratt, senior author and Cary C. Boshamer Distinguished University Professor. “Brown carbon from biomass burning affects millions of people across sub-Saharan Africa every day, yet its chemistry and climate impacts have remained difficult to pin down. Our team set out to bring clarity and real data to a problem that directly influences air quality, human health and global climate models. This recognition validates the importance of that mission and highlights how collaborative science across chemistry, public health and atmospheric research can drive meaningful change.”
Other UNC researchers contributing to the study were Barbara Turpin, a professor in the Department of Environmental Sciences and Engineering at the Gillings School, and Cade Christensen, who received a Ph.D. in analytical chemistry in 2025. They were joined by researchers at North Carolina A&T State University, National Institute of Nuclear Physics in Italy and the University of Genoa.
Across Sub-Saharan Africa, millions of people rely on solid fuels, such as wood, crop residues, grass and even dried animal dung, for cooking and heating. These materials burn incompletely, often at low temperatures, producing heavy smoke rich in tiny particles known as carbonaceous aerosols. One subset of these particles, called brown carbon, is especially important because it absorbs sunlight. This warming effect can alter weather patterns, intensify climate change and reduce visibility. When inhaled, these particles can also contribute to serious health problems.
“Brown carbon is everywhere in regions where biomass is burned,” said Professor Turpin. “But until now, we didn’t fully understand what these particles were made of at the molecular level, how strongly they absorb light or how their properties change as they move through the atmosphere.”
To answer these questions, the team conducted controlled laboratory experiments that mimicked the smoldering fires common in Sub-Saharan Africa. They burned a wide range of representative fuels, including hardwoods, savanna grasses, leaves and cow dung, in a large environmental chamber, carefully measuring the smoke as it formed and aged. The researchers focused on two key questions: How strongly do these smoke particles absorb sunlight? What molecules are responsible for that absorption?
Using real-time monitoring tools, the team measured how light of different wavelengths passed through the smoke. They also collected samples from both the chamber and from outdoor air in Botswana, where biomass burning is widespread during the dry season. In total, they identified 182 individual brown carbon molecules, grouping them into families such as lignin breakdown products, nitroaromatics, coumarins, stilbenes and flavonoids.
This large catalog—one of the most detailed ever produced for African biomass smoke—allowed the researchers to quantify how much each type of molecule contributes to the overall mass and light-absorbing power of the smoke.
The research revealed a strong, direct relationship between the amount of brown carbon in the smoke and how much light the particles absorb, especially at ultraviolet wavelengths. This means that scientists and climate modelers can now better estimate the warming effect of biomass burning by measuring brown carbon mass, which is a major step forward in improving climate predictions.
Another surprising finding came from comparing chamber smoke to real-world air samples from Botswana. Even after being exposed to sunlight and atmospheric chemistry, the Botswana particles still resembled those created in controlled burns of African leaves and cow dung. This suggests that the study’s laboratory measurements closely represent what happens outdoors, strengthening the relevance of the results.
Biomass burning in Africa produces more carbonaceous aerosol than any other region on Earth. These particles influence climate across the Southern Hemisphere and contribute to severe indoor and outdoor air pollution. Understanding what is in the smoke and how it behaves is essential for crafting effective climate models, designing cleaner cooking technologies and developing air-quality policies that protect human health.
“This research provides a foundation that simply didn’t exist before,” said Christensen. “By mapping out the exact molecules involved and how they absorb light, we can help improve climate predictions and inform decisions that affect millions of people.”