Spatial and Temporal Analysis of Particulate Matter and Gaseous Pollutants at Six Heavily Used Traffic Junctions in Megenagna, Addis Ababa, Ethiopia

Abstract

Vehicles are one of the main contributors to outdoor air pollution in urban areas of developing nations. Addis Ababa is experiencing the fastest rate of urbanization with increasing heavy traffic across the city. Megenagna is one of the city’s busiest transportation hubs, connecting traffic to most of Addis Ababa’s lower town via major highways and railways. The ever-increasing air pollution from heavy traffic in the area is an alarming environmental problem for the city. This research aimed to assess and evaluate traffic-related particulate and gaseous pollutants in Megenagna. There were 41 sampling points, 16 of which were near the root of the Megenagna bus station, and the rest 25 were taken on the six main road lines. The samples were collected for the 2-month variations of January and February during the rush hour. Sampling was done using the hand-held portable air test equipment (Model-CW-HAT2005) and Aeroqual Series 500 (2016). Geo-statistical analysis and descriptive and inferential statistical analysis were used. The mean values of PM_2.5, PM₁₀, SO₂, and NO₂ in the Megenagna area were 30.3 ± 2.2 µg/m³_, 58.6 ± 3.1 µg/m³, 777.5 ± 151.2 µg/m³, and 58.6 ± 3.04 µg/m³_, respectively. The difference between sampling locations was statistically significant (p < 0.05), suggesting that there is significant spatial variation between different parts of the study site. Individual comparisons, however, revealed that they are not significantly different from one another on some sites. The hotspot analysis also confirmed that there are hot and cold spots in the distribution of pollution over space and time.