Analysis of the variations and causes of air pollutants in Tangshan City before and after the COVID-19 pandemic from 2019 to 2021

To investigate the anthropogenic influence on air pollution before and after the COVID-19 pandemic, this study analyzed the variations and causes of air pollutants in Tangshan City from 2019 to 2021. It derived the changes in their concentrations and their influencing factors in each time period using an estimation model for emission reduction effects and an inverse distance interpolation method. Accordingly, this study proposed reasonable suggestions for the atmospheric environment control in Tangshan. The results show that: ① From 2019 to 2021, the proportions of primary pollutants in Tangshan remained relatively stable, with PM_2.5 ranking first and photochemical pollution represented by O₃ increasing significantly in recent years; ② The results calculated using the formula for anthropogenic emission reduction show that the control over anthropogenic emissions plays a significant role in constraining air pollution; ③ The analysis based on the inverse distance interpolation method indicates that the peak concentration of PM_2.5 gradually decreased, with the high-concentration distribution shifting toward the city center.