AIR POLLUTION FROM ROAD TRAFFIC AT INTERSECTIONS: EVIDENCE FROM OGBOMOSO, NIGERIA

This paper reports the results of the investigation of air pollution from automobiles at intersections on some selected major roads in Ogbomoso, South Western, and Nigeria. Four sampling routes were considered with ten sampling points (SP1 – SP10) placed 2.0m away from the edge of the road. Priority parameters: SO2, NOx, CO were monitored. The results of SO2, NOx, CO were in the range of 0.02 – 0.09ppm, 0.009-0.039ppm, 1.79-51.38ppm respectively. The concentration of SO2 was highest at SP 6 with value 0.5103ppm. Emission concentration for NOx was found to be highest at SP 6 where traffic congestion and traffic intersection is observed. The highest level obtained for the air pollution indicator of CO was at: SP 9, 6, 3and 10 due to traffic congestion and traffic intersection, where long waiting time for vehicles was observed. All the three monitored air pollutants when compared with AQI level (Air quality index) were in the range of: SO2 – was from very poor to good, NOx- from good to very good, CO – very good to moderate and moderate to poor in different locations. The study concludes that, it has become quite important to understand the role of mobile source emissions on air quality through well-designed studies. This information can provide important input for the formulation of effective air quality management strategies