[Effects of Meteorological Conditions in Summer and Early Autumn on PM and O Pollution in Beijing-Tianjin-Hebei and Surrounding Areas].

PM pollution remains prominent in autumn, whereas O pollution gradually manifests in summer. To understand the dual high characteristics and meteorological effects of PM and O in the summer and early autumn of 2021 in the Beijing-Tianjin-Hebei and surrounding areas, the spatiotemporal distribution characteristics of PM and O concentrations, as well as meteorological conditions, subtropical high index, and weather situation in the Beijing-Tianjin-Hebei and surrounding areas were analyzed. The results showed that PM concentration and DPO （O daily maximum 8h mean minus O concentration at 06：00） from June to September 2021 decreased compared with those in the same period in 2020 and 2022, and high concentrations were mainly occurring in June.