Retrieval of Daily PM2.5 Concentrations Using Nonlinear Methods: A Case Study of the Beijing-Tianjin-Hebei Region, China. - Lijuan Li 003; Baozhang Chen; Yanhu Zhang; Youzheng Zhao; Yue Xian; Guang Xu; Huifang Zhang; Lifeng Guo (Remote. Sens., 2018)