Spatial and temporal distribution of PM2.5 and O3 in north China from 2011 to 2020: Patterns and influence mechanisms

Abstract

Based on PM2.5 and O3 concentration data in North China from 2011 to 2020, the spatial and temporal distribution characteristics of PM2.5 and O3 concentrations were explored using Sen's slope estimation, hot spot analysis, and a spatial center of gravity shift model, and the intensity of the influence of meteorological and socio-economic factors on PM2.5 and O3 concentrations was analyzed using a geographical detector. The results indicate that (1) PM2.5 concentrations in North China exhibit a seasonal pattern of "high in spring and winter and low in summer and autumn" with an average monthly decrease of 0.1625 μg/m3 and an average annual decrease of 1.95 μg/m3. O3 concentrations exhibit a trend of "high in summer and autumn and low in spring and winter" with an average monthly decrease of 0.0108 μg/m3 and an average annual decrease of 0.1296 μg/m3. (2) The centers of gravity of PM2.5 and O3 concentrations migrated in similar directions during the study period with a clear southeastward migration feature. (3) PM2.5 and O3 concentrations possess obvious spatial aggregation characteristics, and the degree of pollution aggregation diminishes with PM2.5 hot spot areas concentrated in southern Hebei Province and cold spot areas concentrated in Zhangjiakou and Hohhot in North China. O3 concentrations are the opposite of PM2.5 concentration spatial aggregation. (4) The single-factor results indicated that ground pressure, average annual temperature, and population density all exerted prominent effects on PM2.5, whereas variations in O3 concentrations were primarily influenced by meteorological factors. (5) Interaction detection demonstrated that the interactions among the influencing factors exhibited a greater explanatory power than did the single factor effect on both PM2.5 and O3 concentration changes.