A model for the estimation of standard deviation of air pollution concentration in different stability conditions

We propose to estimate the standard deviations of air pollution concentration in the horizontal and vertical direction, and , based on Pasquill’s well known equation, in terms of two turbulence parameters, i.e. the wind variance and the Lagrangian integral time scales, on the basis of atmospheric turbulence spectra model. The main idea of the spectral model concerns the treatment of turbulent kinetic energy spectra as the sum of buoyancy and a shear produced part, and modeling each one separately. The formulation represents both shear and buoyant turbulent mechanisms which characterize the various regimes of the Planetary Boundary Layer, and gives continuous values at any elevation and all stability conditions from unstable to stable. The , parameters, included in a Gaussian model have been tested and compared with a dispersion scheme reported in literature, using experimental data in different emission conditions (low and tall stacks) and in several meteorological conditions ranging from stable to convective.