[Trend Changes in Ozone Pollution and Sensitivity Analysis of Ozone in Henan Province]

Based on air quality station data and satellite remote sensing data, the interannual variation characteristics and seasonal variation trends of near-surface ozone (O₃) in Henan province were studied, and the variation in O₃ sensitivity was analyzed. The results showed that the O₃ concentration near the surface of Henan province increased first and then decreased from 2015 to 2020. The highest O₃ concentration was found in 2018, and the annual mean of the maximum daily 8 h moving mean (MDA8) of O₃ was 110.70 μg·m^-3. The difference in MDA8 values among different stations gradually decreased. From 2015 to 2020, the average monthly MDA8 in Henan province showed an upward trend, with a growth rate of 2.46 μg·(m³·a)^-1. According to the MK trend test, except for in Luohe, Nanyang, and Pingdingshan, the rising trend in other cities was significant (P<0.05). The concentration of MDA8 in the four seasons also showed an increasing trend during the 6 years as follows:autumn (19.31%)>winter (17.09%)>spring (16.82%)>summer (7.24%). From 2015 to 2019, the high value of tropospheric NO₂ was concentrated in the northwest of Henan province, and the concentration showed a decreasing trend with a decreasing rate of 0.34×10¹⁵ molecules·(cm²·a)^-1, whereas the tropospheric HCHO showed a slow rising trend with an annual growth rate of 0.19×10¹⁵ molecules·(cm²·a)^-1, with a higher concentration in the northern urban area. The O₃ sensitivity control area from 2015 to 2019 showed that most of the eastern part of Henan province belonged to the VOCs limited category.