- GEOS-CF reveals regional near-neutral and weak day–night O3 reversal signals.
- Non-reversal dominates globally, but reversal covers ~8% of monthly land area.
- Day-only O3 metrics may underestimate exposure in regions with nocturnal persistence.
- Open Access
- Short Communication
GEOS-CF Evidence for Regional Near-Neutral and Weak Day–Night Reversal Signals in Surface Ozone
- Chao He 1,
- Qian Wu 2,
- Yanwen Wang 3,4,
- Peiyue Tu 2,4,
- Chaoqing Huang 5,*
Author Information
Received: 24 Feb 2026 | Revised: 30 May 2026 | Accepted: 23 Jun 2026 | Published: 17 Jul 2026
Highlights
Abstract
Traditionally, near-surface ozone (O3) concentrations are higher during the day than at night. However, analysis of global hourly O3 reanalysis data from 2018–2025 reveals that a day–night reversal (higher nighttime than daytime concentrations) is emerging in many regions. Globally, the day–night O3 difference is diminishing, with a notable reversal already evident in parts of India, China, and selected cities in Western Europe. This shift challenges long-held assumptions about O3 diurnal patterns and has important implications for understanding regional chemistry, air quality assessment, and policy development.
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References
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How to Cite
He, C.; Wu, Q.; Wang, Y.; Tu, P.; Huang, C. GEOS-CF Evidence for Regional Near-Neutral and Weak Day–Night Reversal Signals in Surface Ozone. Global Environmental Science 2026, 2 (3), 273–277. https://doi.org/10.53941/ges.2026.100018.
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Copyright (c) 2026 by the authors.
This work is licensed under a Creative Commons Attribution 4.0 International License.
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