Analysis of the Characteristics of Ozone Pollution in the North China Plain from 2016 to 2020

As a major gaseous pollutant, ozone (O-3) adversely affects human health and ecosystems. In recent years, ozone pollution in China has gradually become a prominent issue, especially in the North China Plain (NCP). To study the long-term spatio-temporal variation patterns of O-3 in the NCP, this study selected 230 monitoring stations in the NCP from 2016 to 2020 as research objects, used the Kriging interpolation method and global Moran's index to discuss the spatial-temporal distribution of O-3, combining meteorological and social statistical data to analyze the causes underlying regional differences. The temporal analysis demonstrated that the O-3-8h average concentrations increased annually from 2016 to 2018 and decreased from 2019 to 2020. The O-3 concentrations were higher in spring and summer (117.89-154.20 mu g/m(3)) and lower in autumn and winter (53.81-92.95 mu g/m(3)). The spatial analysis revealed that O-3 concentrations were low in the north and south of the NCP but high in the central area. The spatial distribution of O-3 exhibited considerable cross-seasonal variability. Both meteorological conditions of high temperature and low pressure increased O-3 concentrations. The spatial distribution of O-3 varied depending on the period. However, the central and western regions of the Shandong Province were constantly characterized by high O-3 concentrations. This pattern has been likely formed by heavy industry in the Shandong Province, as large-scale industrial production and frequent traffic flows produce a large amount of precursors, thereby exacerbating regional O-3 pollution. These characteristics were attributed to emission reduction policies, meteorological conditions, the emission intensity of anthropogenic sources, and regional transport in the NCP. Overall, for cities with heavy industrial facilities in the central NCP, a timely adjustment of the energy and industrial structure, effectively controlling the emission of precursors, promoting new clean energy, and strengthening regional joint prevention and control are effective ways to alleviate O-3 pollution.