Author(s)

R. Cipollone & A. Sciaretta

Abstract

On the evaluation of pollutant gas dispersion around complex sources by means of a Lattice gas model R. Cipollone & A. Sciarretta1 Department of Energetics, University of L 'Aquila, Italy. 1now at ETH Zurich, Switzerland. Abstract For the prediction of local and transient diffusion of pollutant gases from power plants and traffic sources, the Lattice Gas approach is proposed in this paper. The model was parameterised by some non-dimensional numbers that, together with physical data, define completely the case to study. The influence of such numbers is explored and a comparison is made with usual parameterisation of the turbulence in diffusional models. Several simulation tests allow to verify if the results of the model are, in the steady-state limit, coherent with the ones offered by the well validated and universally adopted Gaussian plume equation. 1 Introduction The study of the environmental impact of power plants and traffic sources requires predictive tools that can deal with a large variety of source types, surrounding conditions and diffusional processes. Most of the air quality models used for technical and regulatory purposes and suggested by environmental agencies adopt the steady-state Gaussian plume equation (GPE) as the modelling core. This choice does not allow for taking into account space- and time-variable conditions, since GPE is a steady-state model and merges all the next-to-source effects in the plume rise height term. Even the most recent and complex EPA models (such as AERMOD), that still introduce refinements of the air turbulence parameterisation, terrain description and plume rise calculation, do not remove such limitations. The EPA puff model CALPUFF does take into account transient effects, but is still not adequate to study local effects, since it keeps the use of plume rise height as a way to simulate air- emission interaction, The same can be said of transient Guassian models, that simulate a continuous emission as a sequence of impulsive puffs.

Keywords