| 13 May 2026
Assessment of the impact of tropical anthropogenic and biomass-burning emissions on tropospheric ozone (2007–2021) using the GEOS-Chem model constrained by satellite observations
Abstract. Ozone (O3) is a secondary species formed and is considered a hazardous pollutant in the troposphere. Over the recent decades, tropospheric O3 has undergone significant regional variations. This paper focuses on the impact of the evolution of anthropogenic and biomass-burning emissions in the tropics upon tropospheric and the chemical regimes of O3 using numerical simulations performed of the last 15-years with the GEOS-Chem model. Satellite datasets derived from OMI (HCHO and NO2) and IASI-SOFRID (CO and O3) are used as observational constraints to ensure the most reliable representation of BB and ANT emissions. The results show that the simulation (REF) combining GFAS for BB and CAMS for ANT emission provides the best match with the selected satellite observations.
The analysis of REF-simulation shows that positive trends in tropospheric ozone column (TOC) are observed mainly in the Northern Hemisphere, in Asia regions, Temperate North America, Europe, and some tropical regions (Equatorial Asia and Southern Hemisphere South America), driven by increased of ANT and BB emissions and favourable photochemical conditions.
Sensitivity tests with fixing emissions in the tropical band, reveal that the increase in tropical TOC is mainly due to tropical ANT emissions, which occur in chemical regimes nd: transparent by VOC-limited. Further results highlight that effective mitigation of future increases in TOC will depend mostly on control of ANT NOx emissions in tropical regions, where chemical conditions favour high O3 production, while underlying the marginal role of BB in moderating regional O3 levels.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics.
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