Examining the impacts of air pollution across the tropics
An international collaboration between the University of Exeter, the UK’s Centre for Ecology & Hydrology and James Cook University (Australia) on the impacts of air quality on plant growth and ecosystem productivity across the tropics.
Is air pollution slowing tropical forests and threatening food security?
Ground-level ozone (O3 ) is one of the most damaging air pollutants for plants. It enters leaves, injures cells and reduces productivity. Across the tropics, O3 is rising as cities grow and land is cleared. Yet almost everything we know about O3 damage comes from crops and forests in the temperate Northern Hemisphere.
TropOz is filling that gap. We grow tropical trees and crops under controlled O3, measure how much O3 tropical forests are exposed to, and build what we learn into next-generation models that predict the effects of changing air quality under climate change. Together, these tell us how much O3 is costing tropical forests, farms and the global carbon sink.
Latest findings
Fire-driven O3 adds a hidden carbon cost in the Amazon. Fires release the pollutants that form O3. Simulating the Amazon from 1997 to 2024, we found that O3 damage from fire pollution reduces forest carbon uptake by roughly a quarter as much carbon as the fires release directly, a pathway missing from most carbon budgets. Drought can partly shield forests by closing their stomata, but record fires in 2024 still caused substantial damage. Brown et al. 2026, Communications Earth & Environment
Tropical trees differ widely in their sensitivity to O3. Testing tree species in our chambers, we found large differences in how strongly O3 reduces their growth, and explored which leaf and plants traits may help explain why. Farha et al. 2026, Plant, Cell & Environment
Follow our work on Bluesky, or get in touch if you would like to collaborate.
Project Publications
- Brown, F. et al. (2026). Fire-derived ozone intensifies carbon loss in Amazon forests under extreme droughts. Communications Earth & Environment. doi:10.1038/s43247-026-04047-0
- Farha, M.N., et al. (2026). Ozone susceptibility of tropical tree species. Plant, Cell & Environment, e70777. doi:10.1111/pce.70777
- Farha, M.N., et al. (2025). Examining ozone effects on the tropical C₄ crop Sorghum bicolor. PeerJ, 13, e18844. doi:10.7717/peerj.18844
- Cheesman, A.W., et al. (2024). Reduced productivity and carbon drawdown of tropical forests from ground-level ozone exposure. Nature Geoscience, 17, 1003–1007. doi:10.1038/s41561-024-01530-1
- Brown, F., et al. (2024). Performance evaluation of UKESM1 for surface ozone across the pan-tropics. Atmospheric Chemistry and Physics, 24, 12537–12555. doi:10.5194/acp-24-12537-2024
- Cheesman, A.W., et al. (2023). Impacts of ground-level ozone on sugarcane production. Science of the Total Environment, 904, 166817. doi:10.1016/j.scitotenv.2023.166817
- Farha, M.N., et al. (2023). Examining ozone susceptibility in the genus Musa (bananas). Functional Plant Biology, 50, 1073–1085. doi:10.1071/FP22293
- Vieira, I., et al. (2023). Global reanalysis products cannot reproduce seasonal and diurnal cycles of tropospheric ozone in the Congo Basin. Atmospheric Environment, 304, 119773. doi:10.1016/j.atmosenv.2023.119773
- Brown, F., et al. (2022). The ozone–climate penalty over South America and Africa by 2100. Atmospheric Chemistry and Physics, 22, 12331–12352. doi:10.5194/acp-22-12331-2022