Temporal and Spatial Analysis of PM2.5 Concentrations in Accra Using Integrated Ground-Based and Satellite Sensor Data

Abstract

Air pollution, particularly fine particulate matter, poses a significant public health challenge in urban areas worldwide. This study presents a comprehensive temporal and spatial analysis of PM_2.5 concentrations in Accra, Ghana, utilizing an integrated approach combining data from low-cost ground-based sensors, reference-grade monitors, and satellite-derived sources. Over a 21-month period from April 2019 to December 2020, PM_2.5 levels were monitored across five strategic locations within the Greater Accra Metropolitan Area (GAMA). The findings reveal distinct seasonal trends, with higher PM_2.5 concentrations during the dry season (November to March) and lower levels during the wet season (April to October). This seasonal variation underscores the influence of meteorological conditions on particulate matter levels. Spatial analysis indicates significant variations in PM_2.5 concentrations, with higher levels recorded in densely populated and industrial zones such as Amasaman and Akweteyman. These areas are particularly affected by emissions from vehicular traffic, industrial activities, and biomass burning. A key outcome of this study is the strong positive correlation between ground-based sensor data and MERRA-2 satellite-derived PM_2.5 concentrations, validating the use of satellite data to complement traditional ground-based monitoring. Despite some discrepancies, where satellite data tended to overestimate PM_2.5 levels in 2020 and underestimate in 2019, the integration of these data sources provides a more robust and comprehensive assessment of air quality. The elevated PM_2.5 levels observed in industrial and densely populated areas have significant public health implications. Prolonged exposure to high PM_2.5 concentrations is linked to increased risks of respiratory and cardiovascular diseases. This study highlights the urgent need for targeted air quality management strategies and public health interventions to mitigate these risks. By demonstrating the feasibility and effectiveness of using low-cost sensors in combination with satellite-derived data, this research offers a scalable and cost-effective solution for air quality monitoring in resource-constrained settings. The insights gained from this study can inform policy-making and contribute to improved public health outcomes in Accra and similar urban environments.