Academic journal article Journal of Sustainable Development

Spatio-Temporal Variations in Urban Vehicular Emissions in Uyo, Akwa Ibom State Nigeria

Academic journal article Journal of Sustainable Development

Spatio-Temporal Variations in Urban Vehicular Emissions in Uyo, Akwa Ibom State Nigeria

Article excerpt


The increasing volume of road traffic and congestion strongly impact on air quality in most urban areas of the developing countries. This paper therefore investigates pollution from automobiles during traffic peak periods at intersections on some selected roads in Uyo, Nigeria. It estimates the level of some selected air pollutants which are largely products of internal combustion in motor vehicle engines, namely: Nitrogen dioxide (NO2), Carbon monoxide (CO), Sulphur dioxide (SO2), and Hydrogen sulphide (H2S), in six sample locations. Monitoring of ambient hourly concentration of NO2, CO, SO2 and H2S, took place at six major intersections in Uyo during morning and evening (peak traffic hours) and afternoon ( off-peak hours), hence variations in concentration of these pollutants was determined. Emissions concentration for CO, was found to be higher during the peak periods due to traffic congestion and intersection, where long waiting time for vehicles were observed and however exceeded the Federal Ministry of Environment limits / Standards. Also, the concentration of SO^sub 2^ was alarmingly high, especially in location C. Levels of Nitrogen oxides (NO^sub 2^) and Hydrogen sulphide (H2^sub S^) measured, varied in time and space and was also above the recommended municipal and international standards in all the six locations during the peak traffic period. This finding thus has implications for public health in the region under study as such calls for the need to control emissions of these obnoxious air pollutants in the city.

Keywords: air pollution, carbon monoxide, emission concentration, vehicular emissions, traffic congestion

1. Introduction

Air pollution at all levels is matter of concern the world over. Studies on the effect of air pollution have revealed high potential of suspended particulate matter and gaseous pollutants to cause health challenges on people, ranging from Respiratory infections, and cardiovascular diseases to cardio pulmonary mortality (Sobrata, Srimanta & Raj, 2010). For example NO2 is responsible for immune system impairment, exacerbation of asthma and chronic respiratory diseases: reduced lung function and cardiovascular disease (Schwela, 2000). Semi permanent business operators are mostly at risk of the health challenges associated with these vehicular traffic based pollution. A prevalence of chronic bronchitis and asthma in street cleaners exposed to vehicle pollutants in concentrations higher than WHO recommended guidelines, thus leading to significant increase in respiratory problems (Rachou, 1995).

Modernization, urbanization and increased vehicular use have significantly contributed to air pollution around the world. The use of motor vehicles has increased enormously all around the world since the 1940's. On-road motor vehicles have dominated the markets for passenger and freight transport both in developed and developing countries. Thus, it is estimated that between the years 1950 and 1990, the world car population rose ten-fold, from around 40 million to 400 million (Lixin & Yang, 2003). Although a mixed mode of transport is encouraged, motorized road vehicles are likely to keep their overwhelming dominance of the transport sector in the foreseeable future. One consequence of this has been a growth in the importance of motor vehicles as a source of atmospheric pollution.

The tremendous increase in the mobilization of human society has resulted in phenomenal rise in vehicular traffic on the major roadways. The vehicles discharge an appreciable amount of exhaust emission which consists of poisonous gases like carbon monoxide (CO), sulphur dioxide (SOX), nitrous oxides (NOX), volatile organic compounds (VOCs) to mention but a few. The emissions from the vehicles cause adverse effects on plants, human beings, animals, soil and other environmental constituents. Excessive emissions are released by the vehicles if they are not well maintained and are not properly driven. …

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