Individualization of a representative daily trend of pollutant concentrations as characteristic scenario to be simulated by mathematical models

The paper presents a daily trend of pollutant concentrations, referred to as the “representative day”, i.e. the day for which the overall sum of the mean-square differences between its concentration, averaged within each hour, and the concentrations for all other days at the same hour, is a minimum. The approach also allows the identification of the “least representative day” (the daily series that maximises the mean sum of squared residuals).The purpose of such typifying is that of outlining characteristic scenarios for a given period under investigation and than mathematical models make it possible to attempt simulations of a typical period trend, without the need to simulate all the days of the time interval covered by the typical period

A simple formula for the evaluation of value and position of ground level concentration from a point source

After setting realistic scenarios of the wind and diffusivity parameterizations the Ground Level Concentration is worked out by an analytical solution of the advection-diffusion equation, then an explicit approximate expression is provided for it allowing a simple expression for the position and value of the maximum.Depois de estabelecer cenários realistas das parametrizações do vento e da difusividade, a concentração do nível do solo é elaborada por uma solução analítica da equação de advecção-difusão e, em seguida, é fornecida uma expressão simples para a posição e o valor do máximo de concentração no nível do solo

Solutions of the Atmospheric Advection-diffusion Equation

Some recent results about solutions of the atmospheric advectiondiffusionequation will be presented. Moreover, applications of the solutionsto the study of dispersion phenomena will be suggested.Alguns recentes resultados sobre soluções da equação de difusãoadvecção atmosférica serão apresentados. Além disso, serão sugeridas aplicações das soluções para o estudo de  fenômenos de dispersão

THE GROUND LEVEL CONCENTRATION FROM A POINT SOURCE

The Advection-Diffusion Equation (ADE) is solved for a constant pollutant emission from a point-like source placed inside an unstable Atmospheric Boundary Layer (ABL). The solution is obtained adopting the novel analytical approach named Generalized Integral Laplace Transform Technique (GILTT). The concentration solution of the equation is expressed through an infinite series expansion. After setting a realistic scenario through the wind and diffusivity parameterizations the Ground Level Concentration (GLC) is worked out, then an explicit approximate expression is provided for it allowing an analytic simple expression for the position and value of the maximum. Remarks arise on the ability to express value and position of the GLC as an explicit function of the parameters defining the ABL scenario and the source height

A Synthesis of the Information Given by Temporal Data Series: The Representative Day

The recording of air pollution concentration values involves the measurement of a large volume of data. Generally, automatic selectors and explicators are provided by statistics. The use of the Representative Day allows the compilation of large amounts of data in a compact format that will supply meaningful information on the whole data set. The Representative Day (RD) is a real day that best represents (in the meaning of the least squares technique) the set of daily trends of the considered time series. The Least Representative Day (LRD), on the contrary, it is a real day that worst represents (in the meaning of the least squares technique) the set of daily trends of the same time series. The identification of RD and LRD can prove to be a very important tool for identifying both anomalous and standard behaviors of pollutants within the selected period and establishing measures of prevention, limitation and control. Two application examples, in two different areas, are presented related to meteorological and SO2 and O3 concentration data sets

Turbulent Parameterizations for a Operative air Pollution Model in a Convective Boundary Layer

Apresentamos duas novas parametrizações para um modelo operacional para o cálculo das concentrações ao chão por fonte alta

Evaluation of a time dependent air pollution model with a new vertical turbulent parameterization

The paper presents the evaluation of a model, with a new vertical eddy exchange parameterization, based on a general technique for solving the K-equation, using the truncated Gram-Charlier expansion (type A) of the concentration field and a finite set equations for the corresponding moments. The model can be applied routinely using as input simple ground-level meteorological data acquired by an automatic network. A performance evaluation is shown in the case of continuous emission from an elevated source in a variable boundary layer