Columbia University's Center for International Earth Science Information Network (CIESIN), through NASA's Socioeconomic Data and Applications Center (SEDAC), has released two new datasets, one characterizing historical air quality over the period 1998–2016, and the second projecting urban land extent into the future through 2100 under different shared Socioeconomic Pathways (SSPs).
The first dataset, "Annual PM2.5 Concentrations for Countries and Urban Areas, 1998–2016," provides annual mean estimates of levels of particulate matter (particles with diameters of 2.5 microns or less) in the atmosphere, derived from observations from satellite-based sensors, for countries and urban areas. The national averages are population-weighted. This data set is based on a gridded data set developed by van Donkelaar et al., also available from SEDAC.
The dataset "Global One-Eighth Degree Urban Land Extent Projection and Base Year Grids by SSP Scenarios, 2000–2100" was developed by Jing Gao of the University of Delaware and Brian O'Neill, now director of the Joint Global Change Research Institute at the University of Maryland. The data set characterizes global, spatially explicit urban land scenarios consistent with the SSPs, projected from the base year 2000 to the year 2100 at ten-year intervals, with a spatial resolution of one-eighth degree (7.5 arc-minutes). Such projections are key inputs for analyses of land use, energy use, and emissions and assessments of climate change vulnerability, impacts, and adaptation.