Assessment of Urban air pollution by PM₁₀ and NO₂ and associated impacts and risks through computational analysis in Kigali, Rwanda

Abstract

Air pollution causes around seven million deaths annually worldwide, yet research on the combined impacts of urban pollutants is limited, hindering effective mitigation strategies. This is a concern in Kigali and the East Africa region, where a notable lack of detailed long-term data, limited studies on their health impacts, and a lack of comprehensive methods for assessing urban air pollution impacts and environmental-health risks. This study addresses these gaps, specifically targeting personal exposure to PM₁₀ and NO₂, monitored across six stations in Kigali throughout 2021. These pollutants were selected due to their long-term data availability and significant health-impacts. Utilizing computational analysis of the urban air quality method, we identified vulnerable zones, quality indicators, and impacts and risks associated with urban air pollution. Results reveal that PM₁₀ levels (42.0–56.0 µg m^− 3 and NO₂ levels (15.5–20.4 µg m^− 3) have quality exceeding WHO-2021 guidelines (PM₁₀: 15 µg m^− 3 and NO₂: 10 µg m^− 3) indicating severe air quality issues in Kigali. The variation between monitoring stations was statistically significant (p < 0.05), indicating notable spatial differences within the study area. The probability of exposure by zones (0.14–0.3) is linked to traffic and household emissions. The identified high-impact for PM₁₀ suggests more significant concerns and the need for mitigation, while the low-risk for both pollutants indicates a relatively low immediate health threat. These findings highlight the need for strategic mitigation measures and targeted air quality management policies to control traffic and household emissions, which are essential for improving Kigali’s air quality and safeguarding public health.

Keywords

Air pollution / Impacts / Risks / Quality indicator / Monitoring / Kigali City

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Funding

The Foundation National Centre APELL for Disaster Management (CN APELL-RO)(ROC/Busa/RFB/58/05-31-2022)