An analysis of the sulfur budget and interstate sulfur transport for Colorado

The sulfur budget for Colorado is analyzed in order to understand the importance of interstate transport and natural sources to wet sulfur deposition in the state. A climatological box model is used to separate the various contributions to sulfur deposition. We demonstrate that sulfur dioxide molecules emitted in Colorado have a low probability of wet deposition in Colorado. Therefore, as much as 80 per cent or more of the wet sulfur deposition in the state must be ascribed to external anthropogenic sulfur sources, such as non-ferrous metal smelters and electric powerplants unless some large unspecified natural sulfur source exists.