Monitoring Gaseous and Particulate Air Pollutants near Major Highways in Abeokuta, Nigeria

High traffic volume and traffic congestion on Nigerian roads have led to increase in the concentration of pollutants in the air t posing health risks for human population. This study investigates air quality due to vehicular emissions in some busy roads in Abeokuta metropolis, Nigeria. Air pollutants such as CO, CO2, NO, NO2, SO2, H2S) and suspended particulate matter (SPM) were determined using an active sampler for both dry and wet seasons. The results shows concentration of CO in the urban air ranging from 1.58 – 8.50 ppm during the dry season and 1.22 – 25.75 ppm for wet season, while CO2 ranges from 11800 – 26900 ppm for dry season and 9200 – 26700 ppm in wet season. NO ranged from 0.04 – 2.60 ppm for dry season and 0.02 – 0.66 ppm for wet season while NO2 ranged from 0.09 – 3.40 ppm in dry season and 0.04 – 1.12 ppm in the wet season. SO2 ranged between 0.06 – 2.18 ppm in dry season compared to 0.05 – 0.82 ppm in wet season. SPM varies between 51.00 – 642.25 ppm in dry season and 29.50 - 170.75 ppm in wet season. High concentrations of CO2, NO, NO2, SO2, H2S and SPM were obtained during the dry season compared to the wet season and can be attributed to vehicular emissions due high traffic volume on the roads. The concentrations of pollutants examined were above the World Health Organization (WHO) limits at all the sites