Ozone pollution episodes in North China

The summertime ozone (O3) in eastern China has kept increasing in recent years, accompanying with more frequent persistent O3 pollution episodes (OPEs) in North China. In this project, we analyzed observed O3 data over 2014-2018 to identify a typical weather pattern for OPEs in North China, and further quantified the contributions of regional O3 transports on OPEs. With the help of the global chemical transport model (GEOS-Chem), we could quantified how different processes, such as chemical production, transport, diffuse and dry deposition, influence O3 concentrations in North China. We identified that the central eastern China was the key region that exacerbated OPEs in North China, and the according VOCs reductions in central eastern China would be helpful to alleviate OPEs in North China.