Use of a Tracer to Determine Contribution of a Power Plant to Suspended Particulate Levels

The problem of determining the percentage contribution of a single power plant to ambient levels of total suspended particulates, when there are many sources of identical particulates in a community, has been approached by injecting a gas tracer (SF₆) into the stack effluent of the power plant. On the premise that small particles leaving the stack after an electrostatic precipitator are dispersed in the same manner as a gas, a simple dilution ratio between gas emitted to gas captured is applied to particulates emitted to obtain the contribution to total particulates captured by high-volume air samplers. Tracer tests at the Kanawha River plant of the Appalachian Power Company indicated the plant’s contribution to total suspended particulates was below 10 percent of the total concentration observed in the community. This value was further substantiated when similar results were obtained by multiple regression analyses between stack emissions, wind speed, wind direction, and observed total suspended particulates.