Abstract
This study investigates surface ozone (O3) dynamics in Bhubaneswar (2020-2024) using in situ observations, satellite retrievals, and model-based diagnostics to assess seasonal variability, precursor sensitivity, and related health and agricultural impacts. Compared with the 2010-2015 period, where winter daytime O3 reached ~ 75 ppb, the 2020-2024 record shows moderated winter daytime peaks (~ 51 ppb) but significantly elevated monsoon baselines. Specifically, 24-h monsoon means rose to ~ 25 ppb from ~ 12-15 ppb a decade ago, reflecting a shift toward sustained annual O3 levels. Despite declining seasonal peaks, the frequency of episodic exceedances and estimated crop yield losses has increased. Precursor sensitivity analysis reveals a VOC-limited regime in winter (35%), transitioning to NOx-limited during pre-monsoon (34%) and post-monsoon (29%) periods, with mixed conditions during monsoon (28%). Health risk assessment via the maximum daily 8-h average (MDA8) indicates frequent exceedances of the 50 ppb threshold, particularly in winter and pre-monsoon, signifying chronic exposure risks. Agricultural indices (AOT40, M7, M12, and SUM60) suggest substantial yield losses in paddy and rabi crops, especially during high O3 seasons. Comparisons with Delhi (2024) highlight contrasting O3 formation regimes, where Delhi remains largely VOC-limited due to persistent NOx saturation. The findings emphasize the need for season- and region-specific emission controls, enhanced VOC monitoring, and AI-driven forecasting to support adaptive air quality management in urbanizing eastern India.