Analysis of the PM_2.5–O₃ Pollution Characteristics and Its Potential Sources in Major Cities in the Central Plains Urban Agglomeration from 2014 to 2020

To highlight the characteristics of PM_2.5–O₃ pollution in the Central Plains Urban Agglomeration, spatial and temporal characteristics, key meteorological factors, and source pollution data for the area were analyzed. These data from the period 2014–2020 were obtained from state-controlled environmental monitoring stations in seven major cities of the agglomeration. The results revealed the following: (1) Spatially, the PM_2.5–O₃ pollution days were aggregated in the central area of Xinxiang and decreased toward the north and south. Temporally, during the 2014–2020 period, 50 days of PM_2.5–O₃ pollution were observed in the major cities of the Central Plains Urban Agglomeration, with an overall decreasing trend. (2) A low-temperature, high-pressure environment appeared unfavorable for the occurrence of PM_2.5–O₃ pollution days. Wind speeds of 2.14–2.19 m/s and a southerly direction increased the incidence of PM_2.5–O₃ pollution days. (3) The external transport range in summer was smaller and mainly originated from within Henan Province. These results can provide important reference information for achieving a synergistic control of PM_2.5–O₃ pollution, determining the meteorological causes, as well as the potential sources, of PM_2.5–O₃ pollution in polluted areas and promoting air pollution control.