Field Experiences with Measurement Techniques for Characterizing Toxic Emissions from Coal Fired Boilers

EPA is currently assessing health risks posed by emissions of hazardous air pollutants from electric utility plants. Recent measurements of toxic emissions from coal-fired power plants show the levels of emissions are significantly lower than previously thought. This is largely due to advances in measurement techniques over the past decade leading to more specific measurements with lower detection limits. Nevertheless, many of the available methods for such classes of pollutants as trace metals and semivolatile organic compounds have been validated only for hazardous waste combustion sources and their application to flue gas from coal-fired sources may not be straightforward. This paper describes test methods used to characterize trace metals, volatile and semivolatile organic compounds, hydrogen chloride and hydrogen fluoride, hexavalent chromium, and other substances in coal fired power plants. Field measurements on a utility boiler equipped with an electrostatic precipitator and on a flue gas slipstream treated by a semi-dry scrubber, electrostatic precipitator, and pulse-jet fabric filter are discussed.