Ambient Air Pollution Status of Addis Ababa City; The Case of Selected Roadside

The Objective of the present study was to determine the concentration level, spatial and temporal variation of air pollutants (Carbon monoxide, Volatile organic carbon, Nitrogen dioxide, and Sulfur dioxide) from vehicular emission in ambient air of Addis Ababa city. Measurements were taken at sixty five roadsides sites for all the above selected pollutants. The overall (mean ± SD) of Addis Ababa city roadsides Carbon monoxide, Volatile organic carbon, Nitrogen dioxide, and Sulfur dioxide concentration level were 4.82 ± 3.60 ppm, 317.52 ± 221.52 µg/m 3 , 0.12 ± 0.16 ppm and 0.23 ± 0.20 ppm respectively. Spatial variation were observed for all the pollutants; the highest Carbon Oxide, Volatile organic carbon, Nitrogen dioxide, and Sulfur dioxide concentration were recorded at SS16, SS34, SS39 and SS6 sites whereas the lowest at SS6, SS36, SS6 and SS19 respectively. At most of the sites high Carbon Oxide and volatile organic carbon concentrations were also observed at early in the morning and late afternoon. The temporal variation of Nitrogen dioxide and Sulfur dioxide were not significant at all sites under the study at p<0.05. The morning and the late afternoon peaks indicate that those pollutants were emitted where vehicular traffic was high. The roadside concentrations of all the pollutants under the study were high and needs continuous monitoring and exploring of mitigation techniques.