In 2023, with the end of the COVID-19 pandemic, the production and life of society was fully restored. In this context, the overall
national annual mean concentrations of the six criteria pollutants continued to meet the requirements of China's National Ambient
Air Quality Standards (NAAQS). The air quality significantly improved compared to 2019, when the same level of social activity was held before the pandemic.
From 2019 to 2023, the overall national annual mean concentrations of the six criteria pollutants showed a decline: The decreases of PM2.5, PM10, SO2, NO2, and CO ranged from 15.9% to 28.6%, while O3 achieved a decrease of 2.7%.
