Spatio-Temporal Variations in Carbon Monoxide and Carbon Dioxide Levels in Three Motor Parks in Ibadan, Nigeria

Godson Rowland Ana

doi:10.11648/j.ijema.20150306.15

Abstract

Carbon monoxide (CO) and carbon dioxide (CO2) emissions arising from vehicles and combustion processes in motor parks predisposes to adverse health outcomes and associated health risks. There is dearth of studies and data on air quality in motor parks in Nigeria, hence, the need to assess the levels of CO and CO2 and their relationship with meteorological parameters in three major motor parks in Ibadan, Nigeria. A cross-sectional comparative design was adopted for this study. Akinyele Motor Park (AMP) in Akinyele Local Government Area (LGA), Iwo Road Motor Park (IMP) in Ibadan North East LGA and New Garage Motor Park (NMP) in Ibadan South West LGA were purposively selected and levels of CO and CO2 were monitored for 2 months with appropriate gas meters, meteorological parameters were also monitored using Ventus W155 wireless weather station. Values obtained were compared with WHO and ASHRAE guideline limits. Descriptive and inferential statistics were used for data analysis at p=0.05. CO concentrations (ppm) for AMP, IMP and NMP ranged from 2.0-106.0, 2.0 – 83.0 and 2.0 – 90.0 respectively while the mean CO2 concentrations (ppm) were 395.4 ± 30.5, 356.3 ± 57.1 and 388.1 ± 42.1 respectively. There was a significant positive correlation between CO and CO2 (r=0.258, p=0.000) and also with four meteorological parameters; temperature (r=0.164), rainfall (r= 0.105), heat index (r= 0.134) and dew point (r= 0.127) (p<0.05). A positive correlation was also found between CO2 and four meteorological parameters; temperature (r= 0.276, p=0.000), rainfall (r=0.125), heat index (r= 0.232, p=0.003) and dew point (r=0.028). For the three motor parks, CO concentrations (ppm) were 80% higher than WHO guideline of 9 ppm for 8 hour monitoring. Mean CO2 concentrations (ppm) were within ASHRAE guideline limit of 400 ppm. The study showed that meteorology has influence on CO and CO2 concentrations and motor park users are exposed to high levels of CO. Routine monitoring of CO and CO2 is recommended in order to ensure these emissions do not exceed guideline limits.

Highlights

The global vehicular fleet has increased ten-fold over the last 40 years, and it is predicted to increase even more over the three decades
Afternoon mean Carbon monoxide (CO) concentrations were higher than morning
CO concentrations were 80% higher than WHO guideline of 9 ppm for 8 hour monitoring across the motor parks

Summary

Introduction

The global vehicular fleet has increased ten-fold over the last 40 years, and it is predicted to increase even more over the three decades. Vehicular emissions account for 51% of carbon monoxide, 34% of nitrogen oxides and 10% of particulate matter released each year in the United States [2]. Carbon monoxide (CO) is a colourless, odourless, nonirritating gas produced as a byproduct of incomplete combustion of carbonaceous materials. These materials include petroleum products, coal, natural gas, wood, and plastics. CO can be produced at toxic levels by internal combustion engines, structural fires, industrial operations, and improperly vented heating or cooking appliances [3]. Most of CO emissions (95 - 98%) in a region can be related to anthropogenic activities [4]

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Conclusion