The Anthropogenic Sulfur Dioxide Emissions, 1850-2005: National and Regional Data Set by Source Category, Version 2.86 provides annual estimates of anthropogenic global and regional Sulfur Dioxide (SO2) emissions spanning the period 1850-2005 using a bottom-up mass balance method, calibrated to country-level inventory data. It includes emissions by country and by source category (coal, petroleum, biomass combustion, smelting, fuel processing, and other processes). This data set is developed at the Pacific Northwest National Laboratory (PNNL) and the maps are produced at the Center for International Earth Science Information Network (CIESIN). The data and maps created using the data set are distributed by the Columbia University Center for International Earth Science Information Network (CIESIN).