Long-term exposure to particulate matter and COPD mortality: Insights from causal inference methods based on a large population cohort in southern China

Ying Wang, Zhicheng Du, Yuqin Zhang, Shirui Chen, Shao Lin, Philip K. Hopke, David Q. Rich, Kai Zhang, Xiaobo Xue Romeiko, Xin Deng, Yanji Qu, Yu Liu, Ziqiang Lin, Shuming Zhu, Wangjian Zhang, Yuantao Hao