Spatiotemporal variation of near-ground ozone in Henan province 2015–2021

Real-time ozone (O 3 ) monitoring data from the China National Environmental Monitoring Centre were used to analyze the temporal variation trend and spatial distribution characteristics of ozone pollution in Henan Province from 2015 to 2021. Temporally, the annual average ozone concentration in Henan Province first increased, then decreased, and finally stabilized over the analysis period. The O 3 concentration was the highest in 2018 at 124 μg/m 3 , while the standard exceedance days were the highest in 2019 at 1609 days. The seasonal average value varied, ranking in concentration from the highest to the lowest as summer> spring> autumn > winter. The monthly ozone concentration generally had a unimodal irregular inverted “V” distribution, being at its highest in June and its lowest in December. Over 7 years, the spatial distribution of ozone in Henan Province showed a weak spatial correlation—weak spatial negative correlation—strong spatial positive correlation. The spatial ozone distribution of the four seasons was different for each year, while the spatial aggregation of O 3 for different years in the same season also differed. The spatio-temporal distribution of ozone pollution in Henan Province has had a certain regularity over the past 7 years. Specific O 3 pollution prevention and control measures should, therefore, be formulated for different cities according to local conditions.