ASSESSMENT OF CARBON DIOXIDE EMISSION AT ROAD JUNCTIONS IN THE SOUTHEAST OF NIGER STATE, NIGERIA

This study assesses the levels of atmospheric carbon dioxide (CO2) emission at road junctions in three major cities in the southeast of Niger State in Nigeria, namely: Minna, Bida and Suleja, and identifies measures that improve traffic operations while reducing the emission levels that could have implications on global warming, and hence, climate change. For the study, handheld Crowcon Gasman CO2 gas meter was used to record the CO2 emission readings in parts per million (ppm) during peak (8.00am – 9:00am and 4:30pm – 6:30pm) and off-peak periods (11.30am – 12.30pm and 7:30pm – 8:30pm) of traffic flow at the selected locations within these cities. During peak periods in these locations, the highest emission values of 3236ppm (Park and Garden Junction, Suleja), 3043.5ppm (Mobil Roundabout, Minna) and 3036ppm (BCCC Junction, Bida) were recorded at the road junctions (“hotspots”) with the highest average traffic volume (i.e. motor bikes, buses, trucks and cars) of 4511, 4529 and 3479 respectively. On the average, the level of emission of CO2 recorded at the major road junctions in Suleja, Minna and Bida were 2,856.6ppm, 2,731.1ppm and 2,518.1ppm respectively. The results established that the emission levels in these three cities was approximately eight times more than the internationally accepted safe limits of 350ppm for atmospheric CO2, but less than the Occupational Safety and Health Administration (OSHA) permissible exposure limits of 5,000ppm which has adverse health effects, and may contribute to climate change, in the long term, if unmitigated. The immediate enforcement of traffic congestion mitigation measures for the road junctions in Suleja, the closest to the FCT, Abuja is recommended.