English: Animation of PM 2.5 Concentrations. Movie showing the evolution of PM2.5 concentrations, as inferred by this study, across Eastern China during the four month study interval (April 5, 2014 to August 5, 2014). Concentrations are shown using color gradients and contour lines; the colors (green, yellow, etc.) represent US EPA qualitative health impacts based on 24-hour exposure. Green is “Good”, yellow is “Moderate”, orange is “Unhealthy for Sensitive Groups”, red is “Unhealthy”, purple is “Very Unhealthy”, and dark red is “Hazardous”. Concentrations higher than the upper limit of the maximum EPA classification are shown in gray.