Unraveling overestimated exposure risks through hourly ozone retrievals from next-generation geostationary satellites.

Li, Siwei; Song, Ge; Xing, Jia; Dong, Jiaxin; Zhang, Maolin; Fan, Chunying; Meng, Shiyao; Yang, Jie et al. · Nat Commun · 2025

Where this comes from

Abstract

Accurate ground-level ozone (O<sub>3</sub>) estimation is crucial for assessing health impacts and designing control strategies. Traditional polar-orbit satellites provide limited, one-time measurements, missing O<sub>3</sub>'s diurnal variability. Here, we utilize a next-generation geostationary satellite with ultraviolet capabilities to retrieve hourly O<sub>3</sub> concentrations, achieving high accuracy (R<sup>2</sup> = 0.94) and improving daily maximum 8-hour estimates, particularly in semi-urban areas (R<sup>2</sup> + 0.10, error reduction >7 μg/m³). Our analysis reveals a 30% drop in O<sub>3</sub>-related health risks compared to traditional polar-orbit estimates, with the greatest impact in semi-urban and rural areas where satellite data plays an important role due to the lack of ground measurements. This suggests prior estimates may have overestimated total mortality and urban-rural spillover effects. Our findings underscore the importance of geostationary satellites in capturing O<sub>3</sub> diurnal variability through refined hourly data on photochemical precursors and radiation, providing a scientific basis for health assessments and informing O<sub>3</sub> pollution regulations in China.