Assessing the Atmospheric Concentrations of Carbon Monoxide (CO) and Carbon Dioxide (CO₂) in the Urban Environment in Maiduguri Metropolis

This paper assessed the outdoor atmospheric concentration levels of Carbon Monoxide (CO) and Carbon Dioxide (CO₂) emissions in Maiduguri Metropolis, Borno State, North-Eastern Nigeria. The study was conducted using a multi-gas air quality monitor (S360 Multi-gas Analyzer) in year 2025, across fourteen (14) Emissions Monitoring Stations (EMSs). Data were collected at every EMS for multiple 24-hour periods, from 6am to 3am, at 3-hour intervals, over a period of 2-3 months. Average data were considered for all the EMSs (by point) and at the 3-hour intervals (by time) across the 24-hour periods. Also, maximum data were considered (by time) across the 24-hour period for the city. The results show that average concentrations for CO and CO₂ at the 14 EMSs range between 0.00-3.75 ppm (with a city average of 1.81 ppm) and between 334-671 ppm (with a city average of 575 ppm) respectively. The average daily trends show that CO and CO₂ levels range between 0.00-3.14 ppm and between 523-623 ppm respectively. Similarly, maximum concentrations for CO and CO2 across the day range between 0-10 ppm (with a city maximum-average of 5.88 ppm) and between 604-841 ppm (with a city maximum-average of 753 ppm) respectively. Findings also reveal that for CO, both average levels at the EMSs (except for 24-hour averaging time at Custom flyover and Muna Park) and across the day did not exceed the standard limits recommended by World Health Organization (WHO) and Federal Government of Nigeria (FGN). However, CO2 is found to be higher than the global average of 422.8 ppm. By identifying CO and CO2 levels, this paper provides useful air pollution data and information, highlighting targeted interventions by relevant stakeholders for critical times and areas with elevated pollution levels.