Effect of meteorological parameters on the dispersion of vehicular emission in some selected areas in Kano State -Nigeria

Abstract

In this research work, the results of vehicular emissions in some selected areas in Kano State – Nigeria were investigated. The investigation was meant to detect the presence of CO, PM_2.5 and PM₁₀ using a portable gas sensor (Model- 00014d), air quality detector (Model- 00684c) and particulate meter (Model-00148de). Three areas which include Kofar Wambai (SA₁), Kantin Kwari (SA₂), and Sabon Gari Market (SA₃) were considered with nine sampling points (SP1 to SP9) in each area placed 5.0m away from the edge of the road in downwind direction. The meteorological parameters used were Ambient Temperature, Wind Direction, Wind Speed and Relative Humidity obtained from Malam Aminu International Airport, Kano. The results of the highest level obtained for the air pollution indicator for CO were; 40ppm, at SP₅ for day 1, 47ppm and 41ppm at SP₅ for days 2 and 3 respectively. The concentration of PM_2.5 was highest at SP₂ with a value of 184 μg/m3 on day 3 and the highest concentration of PM₁₀ was observed to be 169 μg/m3 at SP₂ on day 1. However, the three monitored air pollutants when compared with AQI level (Air quality index) were in the range of poor to moderate and moderate to poor for CO at SP₅, poor to very poor for PM_2.5 at all locations of the sample areas and very poor to poor for PM₁₀ at SP₂. It was generally observed from the result that PM_2.5 was found to be the most abundant air pollutant in all three areas. Moreover, the mean association of PM_2.5 levels and selected meteorological parameters during the period of the study is established. Pearson’s coefficient of correlation was applied to study the association between PM_2.5 and meteorological variables. A statistical significant positive association was observed between PM_2.5 with temperature. There was a negative and statistical correlation between PM_2.5 with wind speed, wind direction and relative humidity, which exhibited a washing effect evidenced by its negative correlation with fine particle fractions. The study, clearly points out that wind and temperature are the most important meteorological parameters influencing the behaviour of air pollutants in Kano City.