Computer programs written in BASICA were used to examine various exhaust hood designs for shielded metal arc welding. The breathing zone concentration was found to be an inverse linear function of the computer predicted capture efficiency . This result suggests that simple potential flow models maybe adequate in some cases to apply to industrial processes. In studying the parameters involved in hood design, aspect ratio and flow were found to have a significant effect on the breathing zone concentration. Worker position relative to the hood also was found to be a significant factor. Hood height showed no effect in reducing breathing zone concentrations. Further examination of hood height is warranted.