English

Ukorebi Etim Effiong

doi:10.5897/ajest2016.2107

Abstract

Increasing road congestion and high traffic volume is often times an indicator of atmospheric air pollution. Ibadan, being the largest metropolitan city in southwestern Nigeria, experiences steady influx of vehicular movement on daily bases. The situation is made worse as a greater number of these vehicles are old and poorly maintained. This study therefore investigated the likely impact of high traffic volume along a major roadway (the Ojoo-Mokola road) within the Ibadan metropolis on atmospheric air quality. Eight sampling points along a stretch of the roadway were identified for traffic density and air quality monitoring. Data was collected monthly over a period of four months in the morning peak, off peak and evening peak hours. Air quality parameters, carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), hydrogen sulphide (H2S) and ammonia (NH3) were measured using handheld Crowcon Triple Plus+ and Crowcon Tetra-Portable Multi-Gas Detectors. The average concentration of CO range between 3.25 and 50.8 ppm with highest concentration observed during the morning and evening peak hours. There was a strong correlation (p=0.05) between ambient CO levels and traffic density. Relatively low levels of H2S, and NH3 were detected while NO2 levels were relatively constant (<0.1 ppm). Sulphur dioxide was generally not detected within the study locations. Though this study did not cover the whole city of Ibadan, findings from the eight sampling points suggest that this major stretch of road may altogether not be safe from traffic related problems. There is need for constant monitoring of vehicular emissions to forestall possible air pollution.   Key words: Air quality, vehicular emissions, traffic density, carbon dioxide.

Highlights

The rising number of cars on major roads is an emerging problem in most developing and developed cities (Baldasano et al, 2003; Schrank and Lomax, 2007; Shiva et al, 2007; Kai and Stuart, 2013; Chao et al, 2014)
This study helps strengthen the fact that road intersections usually account for high traffic density and invariably lead to much higher concentration of air pollutants
The Ojoo, University of Ibadan, Sango and Mokola intersections were mostly associated with high traffic volume and congestions

Summary

Introduction

The rising number of cars on major roads is an emerging problem in most developing and developed cities (Baldasano et al, 2003; Schrank and Lomax, 2007; Shiva et al, 2007; Kai and Stuart, 2013; Chao et al, 2014). Rapid urbanization has resulted in uncontrolled growth characterized by poor physical planning, deteriorating environment and increasing vehicular traffic. In such urban environments, traffic emissions are the dominant source of gaseous pollutants, such as NOX, CO and volatile organic. This has created high levels of trafficrelated air pollutants, which have been shown to constitute up to 80-90% of CO emissions. Epidemiological studies have demonstrated adverse health effects of short-term and long-term exposure to traffic-related air polution (Kettunen et al, 2007; Su et al, 2008; Jacobs et al, 2010)

Methods

Results

Conclusion