Analysis of the PM2.5-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 PM2.5-O-3 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 PM2.5-O-3 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 PM2.5-O-3 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 PM2.5-O-3 pollution days. Wind speeds of 2.14-2.19 m/s and a southerly direction increased the incidence of PM2.5-O-3 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 PM2.5-O-3 pollution, determining the meteorological causes, as well as the potential sources, of PM2.5-O-3 pollution in polluted areas and promoting air pollution control.