Investigation of spatiotemporal distribution and formation mechanisms of ozone pollution in eastern Chinese cities...

Severe ground-level ozone (O₃) pollution over major Chinese cities has become one of the most challenging problems, which have deleterious effects on human health and the sustainability of society. This study explored the spatiotemporal distribution characteristics of ground-level O₃ and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021. Then, a high-performance convolutional neural network (CNN) model was established by expanding the moment and the concentration variations to general factors. Finally, the response mechanism of O₃ to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables. The results indicated that the annual average MDA8-90^th concentrations in Zhejiang Province are higher in the northern and lower in the southern. When the wind direction (WD) ranges from east to southwest and the wind speed (WS) ranges between 2 and 3 m/sec, higher O₃ concentration prone to occur. At different temperatures (T), the O₃ concentration showed a trend of first increasing and subsequently decreasing with increasing NO₂ concentration, peaks at the NO₂ concentration around 0.02 mg/m³. The sensitivity of NO₂ to O₃ formation is not easily affected by temperature, barometric pressure and dew point temperature. Additionally, there is a minimum [Formula: see text] at each temperature when the NO₂ concentration is 0.03 mg/m³, and this minimum [Formula: see text] decreases with increasing temperature. The study explores the response mechanism of O₃ with the change of driving variables, which can provide a scientific foundation and methodological support for the targeted management of O₃ pollution.