Increasing attention is being given to fine particulates as a cause of human respiratory and cardiac problems and reduced atmospheric visibility. This has prompted development of ambient air quality standards for PM10 and more recently PM2.5 in the United States, Canada, and other countries. To understand the contribution of stationary sources to ambient PM2.5, data on the mass and chemical composition of primary PM2.5 emissions are needed. Emission data are also needed for gaseous PM2.5 precursors, for example SO2, NOx, ammonia and volatile organic compounds (VOC). Once a complete inventory of chemicallyspeciated source emissions is established . . .