Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Park Dusts from Lagos, Nigeria: Pollution levels, Sources and Exposure Implications.

Abstract

<title>Abstract</title> Dust serves as a primary source and reservoir for polycyclic aromatic hydrocarbons (PAHs) in metropolitan areas worldwide. Therefore, this research investigated the pollution levels, origins, and exposure threats linked with PAHs in dust sampled from twenty vehicle parks in Lagos, Nigeria -one of the fastest growing African cities. Diverse PAH origins were identified with positive matrix factorization (PMF) technique and diagnostic ratios. Total PAH concentrations ranged from 4.81 µg/g to 8.48 µg/g. Four-ring PAHs, particularly Fluoranthene (Flan), were the most prevalent, with concentrations ranging from 0.26 µg/g to 1.33 µg/g in Lagos parks. Benzo(k)fluoranthene from road traffic sources, emerged as the leading PAHs among the seven considered cancer-causing PAHs, ranging from 0.31 µg/g to 0.99 µg/g. The PMF model identified eight sources of PAHs, including biomass combustion, gasoline vehicle exhaust, coke oven emissions, lubricating oil burning, unburnt fossil fuel, diesel combustion, petrol combustion, and fugitive dust. Applying the probabilistic cancer risk model, Lagos average cancer risk from chosen vehicle parks was calculated as 1.27 x 10^{− 5} for children and 1.41 x 10^{− 5} for adults, falling within acceptable risk levels.