Temporal variations in black carbon in the Yangtze River Delta of China: Long-term observations and trends under different pollution processes - Jianhao Ren; Honglei Wang; Yue Tan; Wenjie Wang; Bin Zhu; Tianliang Zhao; Wen Lin; Duanyang Liu; Lijuan Shen; Shuangshuang Shi (Atmospheric Research, 2025)