Impacts of Synoptic Patterns and Meteorological Factors on Distribution Trends of Ozone in Southeast China During 2015–2020

Abstract Surface ozone (O 3 ) pollution under global climate change has become one of the top environmental issues. In this study, we focused on the coastal region in Southeast China with relatively low O 3 precursor's emissions and complicated synoptic conditions, where the O 3 trends and meteorological contributions remain unclear. An increasing trend of O 3 concentrations in the cities (0.3–4.6 μg m −3 yr −1 ) from 2015 to 2020 was observed. Twenty‐three synoptic patterns were clustered based on weather typing method, in which cyclone‐related types and southwesterly type were generally associated with low O 3 concentrations, and high O 3 levels occurred with anticyclone‐related types. Considering both frequency and intensity of synoptic patterns, reconstructed O 3 series captured 46.0%–58.3% of the observed variability. Using Kolmogorov‐Zurbenko filter, an increasing trend of long‐term O 3 was found. By implementing the multiple linear regression model between O 3 concentrations and meteorological factors, the meteorological contributions to O 3 variabilities (44.7%–66.1%) were quantified. The results indicated the meteorological conditions were particularly important in O 3 pollution with the reductions of O 3 precursor's emissions, among which relative humidity, boundary layer height, solar radiation along with low cloud cover were proved to play important roles. The weakening southwest winds along with more anti‐cyclone systems under climate change could increase surface O 3 . This study elucidated the crucial meteorological drivers on the O 3 variability in relatively clean areas and implied the challenges for local governments to mitigate O 3 pollution under global climate change.