Trend Analysis of Vehicular Traffic Contribution to Air Pollution in Urban Cities: A Case Study of Port Harcourt, Nigeria

The study investigated contributions of vehicular emissions to air pollution in Port Harcourt City, Nigeria for two years (24months), 2017-2018. The daytime pattern, monthly pattern, major traffic congested areas and factors that aid dispersion of air pollutants were considered. Using a closed-circuit television, traffic records were obtained at the chosen places by counting the number of vehicles passing at a spot for two hours in the morning, afternoon, and evening (Plate 5.1). For two years, all parameters were monitored once a month (Monday to Friday) in each location (2017-2018). Where appropriate, descriptive analysis, ANOVA, and multiple linear regressions were used to assess the data. The findings demonstrated that the mean concentrations of all pollutants followed a similar pattern in terms of temporal variation and were significantly (P < 0.05) different during the day. Similarly, within the daytime, the mean traffic volume fluctuated greatly and considerably (P < 0.05) between the two research years. Furthermore, all of the pollutants showed a similar pattern in terms of temporal change, with the lowest concentrations in 2017 and the highest in 2018. Statistical analysis revealed that, the concentration of all the air pollutants and traffic volume varied significantly (p < 0.05) between 2017 and 2018.