Spatiotemporal Characteristics of Air Quality across Weifang from 2014-2018

Air pollution has become a severe threat and challenge in China. Focusing on air quality in a heavily polluted city (Weifang Cty), this study aims to investigate spatial and temporal distribution characteristics of air pollution and identify the influence of weather factors on primary pollutants in Weifang over a long period from 2014-2018. The results indicate the annual Air quality Index (AQI) in Weifang has decreased since 2014 but is still far from the standard for excellent air quality. The primary pollutants are O₃ (Ozone), PM₁₀ (Particles with aerodynamic diameter ≤10 µm), and PM_2.5 (Particles with aerodynamic diameter ≤10 µm); the annual concentrations of PM₁₀ and PM_2.5 show a significant reduction but that of O₃ is basically unchanged. Seasonally, PM₁₀ and PM_2.5 show a U-shaped pattern, while O₃ exhibits inverted U-shaped variations, and different pollutants also present different characteristics daily. Spatially, O₃ exhibits a high level in the central region and a low level in the rural areas, while PM₁₀ and PM_2.5 are high in the northwest and low in the southeast. Additionally, the concentration of pollutants is greatly affected by meteorological factors, with PM_2.5 being negatively correlated with temperature and wind speed, while O₃ is positively correlated with the temperature. This research investigated the spatiotemporal characteristics of the air pollution and provided important policy advice based on the findings, which can be used to mitigate air pollution.