Since 2013, China has implemented a series of emission reduction policies, such as the "Clean Air Action" and the "Blue Sky Protection Campaign." Accordingly, the concentrations of air pollutants have generally decreased significantly. However, PM2.5 pollution still occurs in China under unfavorable weather conditions. El Niño–Southern Oscillation (ENSO) is the strongest signal that modulates the interannual variations in the ocean–atmosphere system near the equator. It oscillates between its warm period (El Niño) and cold period (La Niña) and can significantly influence aerosol concentrations.