A NEW MIXED SEGMENT-PUFF APPROACH FOR DISPERSION MODELING

This paper presents a new mixed methodology for realistic and cost-effective simulation of short-term air quality dispersion phenomena using the Gaussian formula. Pollutant dynamics are described by the temporal evolution of plume elements, treated as segments or puffs according to their size. While the segments provide a numerically fast simulation during transport conditions, the puffs allow a proper simulation of calm or low-wind situations. The methodology is incorporated into a computer package (AVACTA II, Release 3) that gives the user large flexibility in defining the computational domain, the three-dimensional meteorological and emission input, the receptor locations, and in selecting plume rise and sigma formulas.