SPATIO-SEASONAL VARIABILITY AND SOURCE INFERENCE OF PM₂.₅ IN ABUJA, NIGERIA: IMPLICATIONS FOR URBAN AIR QUALITY POLICY

Particulate matter (PM₂.₅) poses a critical global public health risk. Urban centers in developing countries, like Abuja, Nigeria, frequently experience air quality levels that exceed international guidelines, yet data remains sparse. This study conducted a spatio-temporal assessment of PM₂.₅ concentrations across three distinct urban locales in Abuja—Karu Abattoir (KD), Nyanya Park (NY), and Asokoro (AS) to capture variability from anthropogenic and traffic influences. 24-hour samples were collected using a [Insert Sampler Model, e.g., BGI PQ100 low-volume gravimetric sampler] during the distinct dry and rainy seasons. PM₂.₅ mass was determined gravimetrically. Concurrent meteorological data were analyzed using Pearson correlation to identify key drivers of pollution dispersion and accumulation. PM₂.₅ concentrations exhibited significant seasonal and spatial heterogeneity. Dry season levels (50.34 – 87.07 µg/m³) consistently surpassed WHO (15 µg/m³), US EPA (35 µg/m³), and EU (25 µg/m³) standards by a factor of 3.3-5.8, with Nyanya Park, a high-traffic zone, recording the highest burden. Air Quality Index (AQI) categorizations ranged from "Unhealthy for Sensitive Groups" to "Unhealthy." Meteorological analysis revealed that low wind speed and high atmospheric pressure during the dry season facilitated severe pollutant accumulation. While wet season precipitation provided some scavenging, it was insufficient to reduce concentrations to safe levels. Abuja experiences a severe and seasonally exacerbated PM₂.₅ pollution problem, positioning it among the most polluted urban centers globally. The findings underscore an urgent public health priority and necessitate immediate, targeted policy interventions, including enhanced continuous monitoring, traffic management, and public awareness campaigns.