Diagnosing ozone formation regimes in Shandong province, China (2019–2023): Implications for volatile organic compounds control policies during the warm season and COVID-19 lockdowns - Lei Sun; Yetong Ma; Yichao Gai; Chuanyong Zhu; Zhenguo Liu; Renqiang Li; Chen Wang; Baolin Wang; Na Yang; Guihuan Yan; Chongqing Xu (Atmospheric Environment, 2025)