Comparative Evaluation of Ambient Air Pollution in Owerri Urban and Its Environs, South-eastern Nigeria

Rapid urbanization and increased anthropogenic activities have intensified air pollution in many Nigerian cities, posing significant environmental and public health risks. This study comparatively evaluated ambient air pollution levels in Owerri urban and its surrounding environments in southeastern Nigeria. Seven sampling locations representing urban, peri urban, and relatively less disturbed areas were selected for field monitoring. Concentrations of major atmospheric pollutants including hydrogen sulphide (H₂S), nitrogen dioxide (NO₂), carbon dioxide (CO₂), carbon monoxide (CO), volatile organic compounds (VOCs), particulate matter (PM₂.₅) and particulate matter (PM₁₀) were measured using portable air quality monitoring instruments. Spatial coordinates were recorded using a Global Positioning System and spatial distribution patterns were analyzed using Inverse Distance Weighted interpolation within a Geographic Information System environment. Results revealed considerable spatial variation in pollutant concentrations across the study area. Carbon dioxide exhibited the highest overall concentrations, indicating the dominance of combustion related activities. Elevated concentrations of CO, PM₂.₅ and PM₁₀ were observed around high traffic and commercial locations, particularly around the World Bank, Orji and Egbu axes of Owerri. Lower concentrations were recorded in less densely populated peripheral areas. The spatial analysis revealed distinct pollution hotspots associated with vehicular emissions, generator use, road dust resuspension and commercial activities. The study highlights the growing air quality challenges in Owerri and recommends continuous air quality monitoring, stricter emission control policies and sustainable urban planning strategies to mitigate pollution and protect public health.