The Community Emissions Data System (CEDS) produces gridded estimates of atmospheric emissions by country and sector from 1750 to the present. These emissions result in increased concentrations of aerosols - small particles in the atmosphere that have a net cooling effect and also influence human health and ecosystems. Emissions data are used by models such as DOE’s Energy Exascale Earth System Model (E3SM) to examine how atmospheric concentrations of aerosols and gases have changed over time and to evaluate whether models are accurately representing atmospheric chemistry and transport processes.