Fugitive Emissions from a Dry Coal Fly Ash Storage Pile

Standardized estimates of fugitive emissions resulting from bulk materials handling are subject to many potential uncertainties based on the material of interest, the specifics of operational handling, and local geography and meteorology. In 2011 EPRI undertook the first of 3 phases of a field monitoring study at a power plant that investigated fugitive emissions of PM2.5 and PM10-2.5 (“PMc” for short) from a large dry storage coal fly ash pile. The results incorporated ambient measurements from May to October of 2011, statistical analyses of meteorological data, use of dispersion modeling to calculate emission factors, and a comparison to AP-42 approaches. Specifically, hourly PM2.5 and PM10 data from beta attenuation monitors (BAMs) was combined with high frequency measurements of light scattering (bscat) to make measurements of background concentrations as well as two sites downwind of a dry fly ash pile at a large coal-fired power plant. Activities monitored on the dry stack included hauling, dumping, and grading. In addition, an unpaved road exists along the base of the dry stack on top of a berm to stabilize the stack. This road is a source of vehicle-generated fugitive dust, and methods were developed to separate out the contribution from the fly ash emissions signal. The results suggest PM2.5 and PMc emission factors for both fly ash and road dust that are considerably lower than those based on AP-42 methods. Planned future work includes similar studies of coal and limestone/gypsum materials.