Observing the Diurnal Variations of Ozone‐NO x ‐VOC Chemistry Over the U.S. From the Geostationary TEMPO Instrument

作者：Xiaomeng Jin, Yo Han Yang, Gonzalo González Abad, Caroline R. Nowlan, Xiong Liu · 发表于：Geophysical Research Letters · 年份：2025 · DOI：10.1029/2025gl116394 · 被引用次数：11 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate、Air Quality Monitoring and Forecasting

Abstract Ground‐level ozone (O 3 ) is an air pollutant formed by the photochemical reactions between oxides of nitrogen (NO x ) and volatile organic compounds (VOCs). A key challenge in mitigating O 3 pollution is to determine whether the O 3 production is NO x ‐limited or NO x ‐saturated. Using the hourly observations of O 3 precursors, formaldehyde (HCHO) and NO 2 , from the newly launched geostationary Tropospheric Emissions: Monitoring of Pollution (TEMPO), we present the first space‐based observations of diurnal variations of O 3 ‐NO x ‐VOC chemistry over the CONUS during 2024 warm season. We integrate a steady‐state model with global simulations to derive the regime thresholds of the HCHO to NO 2 ratio (HCHO/NO 2 ), and identify the O 3 production regimes using the provisional TEMPO products, which have been validated with limited measurements. We find that O 3 production is dominated by NO x ‐saturated regime in the morning but NO x ‐limited regime in the afternoon over major U.S. O 3 nonattainment metropolitan areas.