The level of air quality at public transport stations: The Case of Torhailoch-Ayat main road in Addis Ababa

Abstract

IntroductionThe increase of population and rapid spatial expansion of urban areas generate high travel demand and increase of motorization, which is directly related to air quality of urban environment. The continuous increase in traffic congestion and fuel consumption deteriorates air quality. Public transportation stations are places where people spend a considerable amount of time in the open and get exposed to transport-related emissions. The aim of this study is to investigate the level of air quality at public transport stations in Addis Ababa city along the major route from Torhailoch to Ayat focusing on the concentration of PM2.5, PM10, Air Quality Index (AQI) and CO2. Methods and materialsObservation, vehicle count and field measurements of air quality were used to collect the data. Primary data were collected via field surveying using IQAir AirVisual® pro model air quality measuring device from five public transport stations at peak and off-peak hours. ResultsThis study found that increase in peak hour traffic volume at stations contributes high concentration of PM2.5, PM10, AQI and CO2. High levels of air pollutants were found during peak hours compared to off peak hours. The maximum 30 min’ average concentrations of PM2.5 were found to be 89 μg/m3 during peak hours and 61 μg/m3 during off peak hours, which is far exceeding the WHO air quality standard (35.4 μg/m3). Regression model shows dependent variable (PM2.5) and independent variables is statistically significant. ConclusionThe temporal and spatial distributions of the air pollutants in this study demonstrated that rush hours were the most polluted, having high concentrations of PM2.5 and PM10 while an off-peak hour have low concentration of air pollutants. RecommendationIt is recommended that the city government should encourage zero emission vehicles, provision of efficient public transport and green development in order to reduce the current condition of transport-related air pollutants.