Stack Plume Rise Calculator

About this calculator

Holland's equation, developed in 1953 for meteorological dispersion modeling, estimates how far an exhaust plume rises above a stack's physical top before it levels off and begins drifting downwind — a critical input because the plume's effective height, not the stack's height alone, determines ground-level pollutant concentrations. It calculates rise from the stack's exit velocity and diameter, the ambient wind speed, and a buoyancy term built from the difference between the gas exit temperature and the ambient air temperature (with an optional correction for atmospheric stability).

This calculator takes your stack's exit velocity, diameter, and gas temperature along with wind speed and pressure to estimate the plume rise in meters or feet. Environmental engineers preparing air-quality permit applications, industrial hygienists modeling emissions dispersion, and regulatory compliance staff at power plants and factories use it as a quick screening estimate before running full Gaussian dispersion models like AERMOD, since plume rise directly feeds into how far downwind pollutants travel before reaching breathable air.