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

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

Simulação da dispersão de poluentes em um modelo euleriano considerando coeficientes de difusão dependentes da distância da fonte e o fenômeno de meandro do vento

The aim of this work is to simulate the pollutants dispersion in an Eulerian model considering the wind meandering phenomenon and eddy diffusivities in terms of source distance. The pollutants dispersion model solve analytically the adcevction-diffusion equation by 3D-GILTT technique. To consider the wind meandering in the dispersion model, we decompose the wind in the u and vcomponents and we calculate the autocorrelation functions and wind spectra. The results show a good agreement between the observed and simulated concentrations.O objetivo deste trabalho é simular a dispersão de poluentes em um modelo Euleriano considerando o fenômeno de meandro do vento e coeficientes de difusão dependentes da distância da fonte. O modelo de dispersão de poluentes resolve analiticamente a equação de advecção-difusão pelo método 3D-GILTT. Para considerar o meandro do vento no modelo de dispersão decompomos o vento nas componentes u e v e calculamos as funções de autocorrelação e espectros do vento. Os resultados mostram uma boa concordância entre as concentrações observadas e previstas

Simulação da Dispersão de Poluentes com Reações Químicas na Atmosfera pela Técnica da Transformada Integral

Neste trabalho é apresentada uma nova solução da equação deadvecção-difusão-reação unidimensional transiente usando o métodoGILTT (Generalized Integral Laplace Transform Technique). A idéia bá-sica consiste em modelar as reações químicas considerando estas comoum termo de fonte na equação de advecção-difusão. Cabe salientar que asolução apresentada é analítica

Solução Analítica da Equação de Advecção-difusão Considerando Fechamento não-local da Turbulência e Condições de Vento Fraco

Neste trabalho consideramos o fechamento não-local da difusãoturbulenta na equação de advecção-difusão. Obtemos uma solução analíticapara a equação de advecção-difusão usando o método GILTT (GeneralizedIntegral Laplace Transform Technique). Para testar a nova solução analítica,as concentrações máximas obtidas são comparadas com os dados experimentaisdo experimento de ITT Delhi para condições de vento fraco

Modeling of pollutant dispersion in the atmosphere considering the wind profile and the eddy diffusity time dependent

In this paper we present an analytical solution of the advection-diffusion equation which describes the dispersion of pollutants in the atmosphere considering time dependence in the wind profile and in the eddy diffusivity. A solution is constructed following the idea of a decomposition method upon expanding the pollutant concentration in a truncated series, thus obtaining a set of recursive equations whose solutions are known. Each equation of this set is solved by the GILTT (Generalized Integral Transform Technique) method. For numerical simulations the data of the OLAD experiment, conducted on the 12th of September, denoted OLAD 5, were used and the comparison of model prediction with these data are presented

Analytical solution for a pollutant dispersion model with photochemical reaction in the atmospheric boundary layer

This paper presents an analytical solution for the three-dimensional advection-diffusion equation applied to the dispersion of pollutants that form in the Atmospheric Boundary Layer (ABL). Some substances, when emitted in ABL suffer photochemical reactions producing secondary pollutants, so that a source term is included in the advection-diffusion equation to represent this reaction. The model was applied to simulate the dispersion and transport of ozone (O3) produced by photochemical reactions from nitrogen dioxide (NO2), pollutant emitted by burning fossil fuels by automotive vehicles. The pollutant concentration fields obtained by the proposed solution are compared with mixing ratio data obtained by monitoring the air quality in the metropolitan area of Porto Alegre. From the analysis of the results one verifies that the inclusion of the term proposed to represent a photochemical reaction of a reactive pollutant allows to predict ozone concentrations in the ABL