Chen G, et al. - Using the first national hospital-based prospective registry cohort of stroke in China, researchers investigated the relationship between air pollution and survival after ischemic stroke. Participants in the study included 12,291 patients with ischemic stroke who visited hospitals between 2007 and 2008. By machine learning algorithms with satellite remote sensing, land use information, and meteorological data, participants’ 3-year prestroke exposures to ambient PM₁, PM_2.5, PM₁₀ (particulate matter with aerodynamic diameters ≤1, ≤2.5, and ≤10 μm, respectively) and NO₂ (nitrogen dioxide) were estimated. By analyzing Cox proportional hazards models, 1649 deaths were identified during the 1-year follow-up period. Findings suggested an association of prestroke exposure to PM₁ and PM_2.5 with increased incident fatal ischemic stroke in the year following an ischemic stroke in China. There was no significant association between PM₁₀ or NO₂. Improved air quality can benefit people from stroke recovery.