An Assessment of Vehicular Emissions and Related Health Impacts along Ilorin-Lagos Highway in Nigeria

Abstract This paper assessed in-vehicle and ambient pollution levels from vehicles along Ilorin-Lagos highway covering three distinct 3-hour periods (morning, afternoon and evening) of the day (from 7.30 am to 6.30 pm) along with reported health challenges at six (6) settlements (SP1-SP6) that covered four (4) states. In the case of ambient pollution, Gilair-3 air sampler (GAS) was used to measure sulphur (iv) oxide, (SO2) while ALTAIR 5x Multi-gas Detector (AMD) was used to measure both carbon (ii) oxide, (CO) and sulphur (iv) oxide, (SO2) for all scenarios. Vehicular volume was manually conducted to determine the number of vehicles. Questionnaire was used to assess information on the health challenges faced by the commuters. The concentrations of SO2 ranged from 0.142 - 0.550 ppm (ambient) and 0.037 - 0.097 ppm (in vehicle) using AMD and GAS respectively while CO concentration was between 2.289 - 18.055 ppm using AMD. The results for the in- vehicular pollution revealed that the concentration levels obtained for CO and SO2 inside the vehicles were 6.32 ppm and 0.126 ppm under opened-window condition and 9.53 ppm and 0.274 ppm under closed-window condition respectively (without air condition). The SO2 concentrations obtained from both ambient and in-vehicle were found to be much higher when compared with the FEPA standards; SO2 (0.01 – 0.1 ppm), USEPA standards; SO2 (0.075 ppm) while the CO level obtained from in-vehicle under the two scenarios (opened and closed windows) were below the limit of NESREA standards (10 – 20 ppm) and USEPA standards (35 ppm). Having noticed that these pollutants act under different environmental conditions, the work established statistical evidence that traffic volume affected the pollutants concentrations at most of the sampling points and that the higher the traffic, the higher the emissions and the more the risk of health challenges.