Measurements and simulations of the visual effects of particulate plumes

Abstract In this paper we present field measurements of the visual effects of particulate plumes from two power plants and a copper smelter. The measurements were conducted at downwind distances ranging from 7 to 34 km and for sun-observer angles ranging from 40 to 160°. The visual effects of the power plant plumes were relatively small due to atmospheric dispersion (Kincaid power plant plume in February 1981) or hazy background (Labadie power plant plume in August 1981). The plume from the San Manuel smelter was more visible because of the clean environment. The measurements of plume contrasts range from − 0.15 to + 0.15. Further development of the EPA plume visibility model to improve the treatment of multiple scattering of light and incorporate light absorption by carbonaceous aerosols is described. Teleradiometer measurements and model simulations are in reasonable agreement for cases in which experimental uncertainties are small. The model appears to underpredict forward scattering of light by plume particles.