Ambient Air Pollutions along a Major South-Western Nigerian Road

Abstract

This study investigated the air pollutants in the ambient air of a typical intercity highway in Nigeria. This was to assess the effect of vehicular emission on air quality along the highway. The results showed that NO_X concentrations ranged from 9.9±3.2 to 33.8±3.3 µg/m³ during the wet season and 19.0±1.2 to 35.4±2.3 µg/m³ during the dry season. Sulfur dioxide measured along this highway ranged from 49.7±38.1 to 219±18.1 µg/m³ during the wet season while dry season concentration ranged from 89.1±20.9 to 225.4±57.9 µg/m³. The TSP during the wet season ranged from 54.4±25.6 to 126.8±25.6 µg/m³. These values were below the limits of 250 mg/m³ set by FMEnv., and 150-230 mg/m³ by WHO. However, the TSP measured during the dry season ranged from 85.9±44.6 to 277.8±213.5 µg/m³. The average correlations between NO_X, SO₂, and TSP measured during wet and dry seasons and the traffic density were 0.7, 0.6 and 0.7, respectively. Air pollution along the Nigerian highway is highly linked to vehicular activities.