Assessment of ambient air quality and health risks from vehicular emissions in urban Ghana: A case study of Winneba

Introduction: In Ghana, the road subsector serves as the primary mode of transport, accounting for 96% of passenger and cargo traffic. Air quality issues have been exacerbated by the prevalence of aged and poorly performing vehicular engines, posing significant health risks. This study, therefore, investigated ambient air quality during the dry season along key roadways in Winneba, located in the Central Region of Ghana. Materials and methods: Stationary monitoring devices, including EPAM-7500 particulate monitors and Aeroqual Series 500 gas monitors were used to measure concentrations of Particulate Matters (PM₂.₅, PM₁₀), Carbon monoxide (CO), Nitrogen Oxides (NOₓ), Sulphur dioxide (SO2), and Volatile Organic Compound (VOCs) including temperature and relative humidity. Data collection was conducted using a purposive rotation among the selected roads, with each monitoring session replicated three times. Results: Winneba junction-WindyBay Avenue (WJ’WBA) exhibited the highest concentrations of CO (2125±182.40 µg/m³) whilst the highest level of NOₓ (198±27.01 µg/m³) was at Winneba central-Donkorkyiem (WC’D). PM2.5 concentrations at WJ’WBA was the lowest (871 ± 79.54 µg/m³), while the Control Road (CR) had highest mean concentration of 902 ± 107.16 µg/m³. The PM10 highest mean level was at WJ’WBA (931±51.29 µg/m³) and lowest at the CR (874±90.42 µg/m³). Levels of SO₂ and VOCs were below the detection limits of the gas monitors. In all, levels of the measured pollutants did not differ significantly (p<0.05) between the sampling locations, but exceeded the pollution thresholds established by the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA). All monitored roads were classified as "extremely polluted" based on the Air Quality Index (AQI). The Exceedance Factors (EF) confirmed the severity of pollution levels. Statistical analyses, correlation and regression methods, indicated no significant relationship between weather conditions and air pollution levels. Conclusion: These findings underscore the severity of air quality issues in Winneba and the urgent need for enhanced monitoring systems including the implementation of regular vehicular emission testing and the use of bioindicators for monitoring vehicular pollutants to mitigate both human and environmental health risks.