Long-term effect of exposure to lower concentrations of air pollution on mortality among US Medicare participants and vulnerable subgroups: a doubly-robust approach oleh Mahdieh Danesh Yazdi, PhD, Yan Wang, ScD, Qian Di, ScD, Weeberb J Requia, PhD, Yaguang Wei, PhD, Liuhua Shi, ScD, Matthew Benjamin Sabath, MA, Francesca Dominici, ProfPhD, Brent Coull, ProfPhD, John S Evans, ScD, Petros Koutrakis, ProfPhD, Joel D Schwartz, ProfPhD