Significant changes in autumn and winter aerosol composition and sources in Beijing from 2012 to 2018: Effects of clean air actions

Jiayun Li, Wenkang Gao, Li‐Ming Cao, Yao Xiao, Yangmei Zhang, Shuman Zhao, Zan Liu, Zirui Liu, Guiqian Tang, Dongsheng Ji, Bo Hu, Tao Song, Ling‐Yan He, Min Hu, Yuesi Wang