Modelling the dispersion of atmospheric pollutants using two dimensional advection diffussion equation
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Date
2011
Authors
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Journal ISSN
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Publisher
University of Dar es Salaam
Abstract
This work focuses on the development of two dimensional advection-diffusion equation and use
it to model atmospheric pollutant dispersion in the effort to study the behaviour of the dispersion
of pollutants in the air A two dimensional atmospheric dispersion mathematical model for
computation of the ambient air concentration of reactive emitted from ground ]eve] sources is
described. The advection-diffusion equation uses meteorological data obtained form the literatures
to model air pollutants dispersion. The model is presented in form of partial different equation
(pde). Different pollutants, how- ever, may present different variability characteristic due to their
specific emission patterns, rates of diffusion, depth and transformation behaviours like
atmospheric reactions. The study of pollution transport phenomena using the advection- diffusion
equation was done in three consecutive steps. Firstly we derived the advection-diffusion equation
from physio-chemical laws governing the transport phenomena and discuss its properties together
with initial and boundary conditions. Secondly we discretized the Advection- Diffusion equation
and suggest a positive difference method to solve numerically a two dimension Advection-
diffusion equation. Lastly we tested the method to generate approximate numerical solutions
simulating different scenarios of pollution transport in a two dimensional domain. The outputs
presented in graphical form that like other parameters, depth has significant influence on the
dispersion of pollutants. The drift velocity of air moves the polluted zone from one region to
another at the rate which is proportional to its magnitude. The eventual chemical reaction between
the pollutant, the depth and one or more air components acts as a pollution sink or fall out and
hampers the horizontal expansion of polluted zone.
Description
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Keywords
atmospheric, dispersion, pollutants
Citation
Ali, A.O.(2011) Modelling the dispersion of atmospheric pollutants using two dimensional advection diffussion equation. Masters dissertation, University of Dar es Salaam. Dar es Salaam.