Elsevier

Atmospheric Environment

Volume 98, December 2014, Pages 158-167
Atmospheric Environment

A study of the effects of vehicle emissions on the atmosphere of Sultan Qaboos University in Oman

https://doi.org/10.1016/j.atmosenv.2014.08.049Get rights and content

Highlights

  • Predicting concentrations of CO, NOx, and CO2 released from traffic using CALPUFF.

  • Sultan Qaboos University was selected as study domain.

  • Simulation results demonstrate the violation in the concentrations of pollutants.

Abstract

Traffic jams have become a serious matter at Sultan Qaboos University (SQU) in Muscat, Oman due to an increase in student numbers. Therefore, the main objective of this research study is to apply the information gained by running CALPUFF software to model and investigate the concentration dispersion of the three most dominant vehicle emissions carbon monoxide (CO), mononitrogen oxides (NOx), and carbon dioxide (CO2) at SQU. The study was divided into two main parts: a line source study focused on investigating the dispersion of CO, NOx, and CO2 for a street located within the university's boundaries, and a study of the university domain as an area source. The study was based on statistical data collected on April 2, 2014, between 00h00 and 23h00 Local Standard Time (LST). Information related to both surface and upper air quality was obtained and processed into data files which were used to activate CALMET. For selecting vehicle emission factors, a comparison between different studies was conducted. CALPUFF line source case study simulation results showed that CO levels were within the allowable concentrations assigned by the United States' Environmental Protection Agency (EPA) standards. On the other hand, the NOx and CO2 simulated results were higher than the allowable amounts according to the EPA emission standards. Moving to the area source study, results demonstrated that the three pollutants significantly exceeded the allowable standards. The top five maximum concentrations were located near the origin of the study domain for both line and area source measurements. At the times that maximum concentrations were recorded, the wind was blowing from the sea toward the land. As a result, the greatest accumulation of pollutants was located close to the domain of the area of study.

Introduction

CALPUFF is considered one of the most powerful environmental modeling programs. It has been used by many researchers to investigate and model pollutant concentrations as well as to simulate the effect of the meteorological and geophysical conditions on the dispersion of a targeted pollutant. CALPUFF can be run for any specific location around the world and for any modeling type period selected by the user. Due to its flexibility, CALPUFF has been used in several research studies.

Over the past years, several CALPUFF-aided case studies have been published. Abdul-Wahab et al. (2011a) used CALPUFF software to measure and simulate the dispersion of sulfur dioxide (SO2) at the Mina Al-Fahal Refinery in the Sultanate of Oman. The study compared the application of this modeling system with Abdul-Wahab's (2003) study of the same location using the Industrial Source Complex Short Term (ISCST) model. Abdul-Wahab et al. (2011b) conducted another case study simulating the dispersion of sulfur dioxide (SO2) at Sohar Refinery in the Sultanate of Oman. Abdul-Wahab et al. (2012) evaluated the impacts of a SO2 release on workplace and ambient air quality at Al-Noor Production Station located in the southern desert of the Sultanate of Oman.

The impact of nitrogen oxides (NOx) has attracted the attention of several researchers, including Abdul-Wahab et al. (2013). The main focus of that study was to examine the impact of a region's geophysical and meteorological conditions on the dispersion of NO2 from a proposed refinery located in Canada. Another study for similar pollutant was done by Yu and Stuart (2013). Ghannam and El-Fadel, 2013a, Ghannam and El-Fadel, 2013b) and Tian et al. (2013) considered as examples of studies for which CALPUFF software was used to study concentrations of multiple pollutants. Recently, Abdul-Wahab et al. (2014) used CALPUFF to study the effect of meteorological conditions on the dispersion of an accidental release of hydrogen sulfide (H2S).

Although a significant amount of research related to CALPUFF modeling software has been published, few studies have considered the effect of vehicle emissions or investigated the dispersion of CO, NOx, and CO2 concentrations for line sources. The James Bay AirQuality Study Team (2009) and Rosemont Copper Company (2011) considered line source emissions in their research, but this most recent research paper concentrates on applying the knowledge gained by running CALPUFF modeling software to model the dispersion of CO, NOx, and CO2 concentrations. Despite the fact that traffic jams have become a serious matter there, the main aim of this study was to investigate the effect of vehicle emissions on the Sultan Qaboos University (SQU) environment.

This study has been divided into two main parts: a line source study which focuses on investigating the dispersion of CO, NOx, and CO2 for a street located within the university boundary, and a study which consider SQU as an area source of pollutants.

Section snippets

Description of the study area

Located in Muscat, the capital city of Sultanate of Oman, SQU was the first public university in the Sultanate. Fig. 1 shows a map of Oman with the location of the university, the study domain, highlighted. The construction of SQU commenced in 1982 in a total area of 6.8 km2; the first batch of students enrolled in 1986. The university initially started with five main colleges: Engineering, Medicine, Education, Agriculture, and Science. A year later, the College of Arts was established, with

Results and discussions

Fig. 6 shows a terrain map for the study location. As can be seen from the map, the terrain consists mainly of enormous ranges in height, which is related to the mountainous terrain that surrounds Muscat. Since Muscat is a coastal city, the meteorological conditions of the land are strongly affected by the sea. Result analyses will be divided into two parts: line source emissions and area source emissions.

Conclusion

It is crucial to make use of software models to investigate the influence of the meteorological and the geophysical conditions on the dispersion of vehicle emissions in the environment. For this purpose, the impact of vehicle emissions on SQU environment was examined. Three vehicle pollutants, CO, NOx, and CO2, were considered in the case study. The study was divided into two main sections: a line source study, which focused on investigating the dispersion of the selected pollutants for a

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