Observational study reveals fluctuating near-ground ozone levels in Henan Province, highlighting the need for city-specific pollution prevention strategies.
Key Points
To evaluate the temporal variation trends and spatial distribution characteristics of near-ground ozone pollution from 2015 to 2021.
Analyzed real-time ground-level ozone (O3) monitoring data gathered between 2015 and 2021 from the China National Environmental Monitoring Centre.
Assessed multi-year annual, seasonal, and monthly variations alongside spatial correlation and aggregation patterns across municipal regions.
Annual average ozone concentrations peaked in 2018 at 124 μg/m3 before stabilizing, while standard exceedance days reached an overall maximum of 1609 days in 2019.
Seasonal concentrations ranked consistently as summer > spring > autumn > winter, displaying an inverted V-shaped monthly curve that peaked in June and reached its lowest point in December.
Spatial patterns over the 7-year timeframe transitioned from weak spatial correlation to weak negative correlation, ultimately shifting to strong positive spatial aggregation.