Air Pollution Exposure and Public Transport in Addis Ababa: Vulnerability Scoping Study

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The effects of air pollution on human health are well documented in a range of epidemiological studies; exposure increases the risk of lung cancer, heart disease, bronchitis and other cardiorespiratory conditions. Whilst, air pollution is considered to impact on all groups, particularly when exposed over prolonged periods of time, some groups are considered to be more susceptible than others. This scoping study explores the vulnerability of commuters, bus drivers and street vendors who are exposed to poor air quality on buses or at bus stations via the deployment of low-cost PM sensors in both indoor and outdoor settings. The study also probed perceptions of commuters, street vendors and bus drivers regarding air pollution. Findings underscore the vulnerability of these groups to air pollution and suggest that those from low socioeconomic backgrounds are likely to face a triple burden of exposure both at home, in work or during commutes. The air pollution levels at both bus station (outdoor) and bus (indoor) settings regularly exceed World Health Organization (WHO) guideline amounts. Bus station PM2.5 were measured to be on average 113 ± 99 µg/m3 and peaked at 323 ± 203 µg/m31. Further to this, air pollution levels tend to peak during early morning and late evening hours, consistently reaching unhealthy levels throughout the day. Measured levels of PM2.5 on buses ranged between PM2.5 49 ± 19 µg/m3 and 105 ± 45 µg/m3 on journeys measured. Survey findings suggest that survey respondents are relatively cognizant of their inherent vulnerability to air pollution, perceiving their vulnerability on a scale of 1-5 at an average of 3.87/5 (five indicating extreme levels of vulnerability). Respondents demonstrated a mixed understanding of the potential sources of air pollution, though this is to be expected given the relative lack of knowledge regarding air pollution in many societies.