Evaluation of Gaussian Plume Model against CFD Simulations through the Estimation of CO and NO Concentrations in an Urban Area

Mahmoud Bady

doi:10.3844/ajessp.2017.93.102

Abstract

Dispersion of air pollutants, Carbon monoxide (CO) and Nitrogen oxide (NO), due to three point sources and a high-density traffic road in an urban area located near the center of Tokyo, Japan was studied using two different approaches. The first is an analytical approach using Gaussian Plume Model (GPM) while the second is a numerical approach using Computational Fluid Dynamics (CFD) simulations. In the first approach, the study area was divided into a fine grid and the traffic road was treated as a number of continuous adjacent stacks. The GPM was applied upon each stack and the concentration at each receptor was calculated using the principle of superposition. CFD simulations were carried out where steady state analysis was adopted and the standard k-e turbulence model was used. The concentrations calculated with the two approaches were compared together. The study results show that the agreement between the concentrations estimated by the two approaches was good in low-density built-up locations within the study area while significant deviation was obtained for high-density locations. Such result reflects the fact that the GPM is poor in predicting the actual concentrations in cases of densely urban areas.

Highlights

During the last few decades, investigation of air pollutants transportation and dispersion in urban areas has become of major concern for the protection of air quality and for compliance with air pollution regulations
The origin is transferred to the center of the considered stack and the modified x-axis is set in the same direction of the wind, while the modified y-axis is taken perpendicular to the wind direction
The objective of the present study was to evaluate the performance of Gaussian Plume Model approach in comparison with a numerical approach using Computational Fluid Dynamics (CFD) simulations, through a study of air pollution problem in an urban area located near the center of Tokyo, Japan

Summary

Introduction

During the last few decades, investigation of air pollutants transportation and dispersion in urban areas has become of major concern for the protection of air quality and for compliance with air pollution regulations. The importance of pollutants transport investigation arises from the increased levels of pollutants in the atmospheric air of urban areas. Such increase has many reasons such as the continuing expansion of industries and the increased usage of motor vehicles coupled with population growth, especially in the major urban areas. These sources introduce a variety of air pollutants in large quantities into the atmosphere. Air pollution modeling has become an indispensable tool to assess the ambient air quality and to maintain pollutants level within permissible limits. Air pollution modeling has become a primary tool in most air quality assessments

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