MATHEMATICAL MODELLING OF URBAN TRAFFIC AIR POLLUTION IN MINNA METROPOLIS, NIGERIA

Abstract

ABSTRACT Vehicular exhaust emissions are a dominant source of air pollution and contribute significantly to greenhouse gases and human health problems. An improved dispersion model designed to estimate pollutant concentrations near travel ways of urban streets was developed and its performance evaluated. The model has four inbuilt parameters namely; the aerodynamic coefficient, the wind speed offset, the effective release height and the street wind turbulence coefficient. The model was calibrated with field data collected in Mobil-Bosso Road in Minna using a gas analyzer with detector tubes. The model’s performance was evaluated and compared with Calder’s and OSPM models. The model adequately simulated the concentrations of the pollutants and resulted in a percent error margin less than 10 for all the pollutants considered. The model was validated with data collected in a Copenhagen (Denmark) study for Nitrogen dioxide and was found to over predict the measured concentrations by 4%, which was considered adequate. The model requires less user inputs and modeller expertise and could be used by local authorities or air quality monitoring units in a variety of applications including, but not limited to, air quality and traffic management, urban planning and population exposure studies.