Investigating vertical distributions and photochemical indications of formaldehyde, glyoxal, and NO2 from MAX-DOAS observations in four typical cities of China - Qianqian Hong; Jingchen Xing; Chengzhi Xing; Baixue Yang; Wenjing Su; Yujia Chen; Chengxin Zhang; Yizhi Zhu; Cheng Liu (Science of The Total Environment, 2024)