Lateral Dispersion from Tall Stacks

Abstract

Hourly ground-level concentrations of SF6 at downwind distances ranging from 0.5 to 50 km were observed by the Electric Power Research Institute (EPRI) on dense monitoring networks around power plants at Kincaid, Illinois, and Bull Run, Tennessee. Sigma y on given sampling arcs was estimated by a robust procedure. Over 160 h of data are available from monitoring arcs located at about five downwind distances, which show that σy is close to linear with downwind distance, x. During unstable conditions, σyu/w*x=0.6. When all the data are plotted together, the following empirical equation is valid: