Enhanced anthropogenic and biogenic interaction by approaching typhoons deteriorates cross-regional ozone pollution in China.

Tropospheric ozone (O3) pollution is becoming the primary obstacle to the improvement of air quality in China, especially in the Pearl River Delta (PRD) region. Because O3 pollution episodes are closely related to synoptic weather patterns (SWPs), historical episodes (from 2006 to 2019) were classified according to SWPs using the Lamb‐Jenkinson method. Monitoring network and weather reanalysis data, emission inventories, and satellite retrievals were used to investigate the spatiotemporal characteristics and influences of O3 pollution. It was found that easterly (P_E), anticyclone (P_A), and typhoon‐related (P_NE) SWPs accounted for 75% of all O3 pollution episodes. In the PRD, the O3 formation mechanism showed clear differences under different SWPs, which were affected by local emissions under P_A, whereas regional transmission dominated under P_E and P_NE. The O3 peak concentration was strongly associated with temperature, solar radiation, and shifting of the sea‐land breeze. A delayed shift of land to sea breeze caused by SWPs often caused the O3 peak to appear in the late afternoon. Finally, stepwise regression was used to explain individual meteorological parameters contributing to O3 formation. It was found that the formation of O3 pollution under P_E and P_NE was associated with increases in temperature and radiation, while P_A was mainly affected by the increase of the overnight accumulation of O3. This study advances our knowledge of the formation mechanism of O3 pollution and provides scientific support for effective O3 pollution control.

No abstract