Open AccessArticle by Ping Du 1, Xiaoling Nie 1, Hongtao Liu 2, Zhiru Hou 2, Xiaole Pan 3, Hang Liu 3, Xinghui Liu 1, Xinfeng Wang 4, Xiaomin Sun 4 and Yan Wang 1,* 1 School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China 2 Renhezhihai Intelligent Technology (Shandong) Co., Ltd., Weifang 261000, China 3 Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China 4 Environment Research Institute, Shandong University, Qingdao 266237,...