Optical properties, molecular characterizations, and oxidative potentials of different polarity levels of water-soluble organic matters in winter PM2.5 in six China's megacities

Tian Zhang, Zhenxing Shen, Shasha Huang, Yali Lei, Yaling Zeng, Jian Sun, Qian Zhang, Steven Sai Hang Ho, Hongmei Xu, Junji Cao