Over recent decades, effective air pollution policies have substantially reduced anthropogenic emissions across China, making biogenic sources increasingly important contributors to air quality. These natural emissions—terpenoids released by vegetation and nitrogen oxides from soils—are strongly temperature-sensitive, spiking dramatically during heatwaves. While scientists have separately studied how heatwaves boost biogenic volatile organic compounds (BVOCs) and soil nitrogen emissions, the chemical interactions between these co-elevated biogenic fluxes remained completely unconstrained. Based on these challenges, there is an urgent need to investigate how temperature-driven natural emissions interact with each other and with atmospheric chemistry during extreme weather events.
A multinational research team led by Fudan University, in collaboration with Duke University, the University of California, Irvine, and other institutions, publishes (DOI: 10.1016/j.ese.2026.100720) these findings on June 12, 2026, in Environmental Science and Ecotechnology. The study integrates ground-based observations, satellite data, and chemical transport modeling to unravel the mechanisms behind secondary pollution amplification during China's record-breaking 2022 summer heatwave.
The researchers found that soaring temperatures during the 2022 heatwave—which pushed the average summer temperature from 23.0°C to 25.0°C, with maxima reaching 46.4°C—triggered massive surges in both biogenic terpenoid emissions and soil nitric oxide (NO) release across the Yangtze River Basin. Isoprene, the dominant terpenoid species, increased by more than 130% in emission rates compared to the 2020–2021 average, a trend independently confirmed by satellite observations of formaldehyde (HCHO) column densities. Crucially, the study uncovered a previously unknown synergistic mechanism: rising biogenic terpenoids generate reactive peroxy radicals (RO2) that dramatically enhance atmospheric oxidation capacity. These radicals accelerate the conversion of soil-emitted NO to nitrogen dioxide (NO2) without consuming O3—a chemical pathway that bypasses the normal ozone-depleting reaction between NO and O3. In nitrogen oxide (NOₓ)-limited regions where this mechanism is most potent, the team documented a 21% regional ozone increase and a substantial boost in SOA formation, with SOA concentrations rising by up to 4 μg m⁻³. The researchers also found that future warming under the Shared Socioeconomic Pathway 5-8.5 scenario could intensify these effects, with a 5°C temperature increase nearly doubling the impact.
"We were genuinely surprised by how powerful this natural feedback loop turned out to be," the authors said. "For years, we've been patting ourselves on the back for reducing anthropogenic emissions, but what we're seeing here is nature pushing back in a way we hadn't anticipated. The vegetation and the soil are essentially conspiring during heatwaves—the trees pump out these reactive compounds that supercharge the atmosphere's oxidation capacity, which then grabs the nitrogen coming out of the soil and turns it into ozone much faster than we thought possible. If we don't account for this in our pollution control strategies, we could be chasing our tails as the climate continues to warm."
These findings carry profound implications for air quality management in a warming world. As anthropogenic NOₓ emissions continue to decline across China and other regions, the geographic extent of NOₓ-limited regimes—where this biogenic-soil synergy is most potent—is expanding. This means that the relative importance of natural emissions will only grow, potentially offsetting the air quality gains expected from further emission reductions. The study also cautions that large-scale afforestation, while vital for carbon sequestration, could inadvertently worsen local air quality if not planned with atmospheric chemistry in mind. Forest management strategies must integrate ecological and atmospheric feedbacks to ensure that greening efforts support rather than undermine regional air quality targets. The researchers urge policymakers to incorporate dynamic biogenic emission baselines into future climate adaptation and pollution control frameworks.
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References
DOI
10.1016/j.ese.2026.100720
Original Source URL
https://doi.org/10.1016/j.ese.2026.100720
Funding information
This work was supported by the National Natural Science Foundation of China (42375178/42377098), the National Key Research and Development Program of China (2022YCF3703004) and the Natural Science Foundation of Shanghai (23ZR1406100).
About Environmental Science and Ecotechnology
Environmental Science and Ecotechnology (ISSN 2666-4984) is an international, peer-reviewed, and open-access journal published by Elsevier. The journal publishes significant views and research across the full spectrum of ecology and environmental sciences, such as climate change, sustainability, biodiversity conservation, environment & health, green catalysis/processing for pollution control, and AI-driven environmental engineering. The latest impact factor of ESE is 14.3, according to the Journal Citation ReportsTM 2024.