Polycyclic Aromatic Hydrocarbons (PAHS) in Urban Air Pollution. Environmental Persistence, Atmospheric Transport and Carcinogenic Risk in Uvwie Local Government Area, Delta State, Nigeria

AHs are long-lasting and dangerous atmospheric pollutants that form during incomplete combustion, and their increasing occurrence in urban environments has become a significant environmental and public health issue in rapidly urbanising areas. This research was carried out to assess the frequency, environmental stability, atmospheric transportation pattern and carcinogenic hazard of airborne PAHs in Uvwie Local Government Area, Delta State, Nigeria. The adopted design was a longitudinal field-based design, which included ambient air measurements at 86 georeferenced sampling points during a 9-month time span, followed by solvent extraction, GC-MS identification of 16 priority PAHs, molecular distribution analysis, diagnostic ratio analysis, multivariate analysis, classification of hotspots, and estimation of the risk of inhalation cancer using benzo[a]pyrene The findings indicated that the major congeners were fluoranthene (13.68 ng/m3), pyrene (12.91 ng/m3), and phenanthrene (11.54 ng/m3), and the total mean 16 PAHs was 111.59 ± 20.14 ng/m3. The high-molecular-weight PAHs prevailed across all land-use classes, indicating strong persistence and combustion effects. The greatest pollutant load was observed in high-traffic corridors, and because of dry-season conditions, Σ16 PAHs was at 130.56 ± 15.23 ng/m3 in high-traffic areas as compared to 93.14 ± 12.47 ng/m3 during the wet season. Benzo[a]pyrene was the main contributor of 50.73% of total BaPeq and the total ILCR was 1.03 × 10⁻5, with children and roadside occupational groups at a higher relative risk. The paper finds that Uvwie is an urban exposure (combustion) environment with significant carcinogenic meaningfulness of persistent airborne PAHs indicative of need of air-quality intervention.