van Donkelaar, A., R. Martin, M. Brauer, N. C. Hsu, R. Kahn, R. Levy, A. Lyapustin, A. M. Sayer, and D. Winker (2016), Global Estimates of Fine Particulate Matter using a Combined Geophysical-Statistical Method with Information from Satellites, Models, and Monitors, Environ. Sci. Technol., 50, 3762-3772, doi:10.1021/acs.est.5b05833.