The potential health risk assessment of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) on the human respiratory system within the ambient air of automobile workshops in Benin City, Nigeria

Abstract

This study investigates the potential health impacts of PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) in the ambient air of automobile workshops in four different districts of Benin City. A total of 180 representative samples were collected from artisans’ workshops in both wet (April to November) and dry (December to March) seasons using the Apex2IS Casella standard pump for a period of 1 year. The PM_2.5 was screened through a polyurethane foam (PUF) and collected on a quartz filter. The resultant PM_2.5-bound PAHs were extracted and analysed using gas chromatography equipped with a flame ionisation detector (GC-FID). The results revealed that the annual average concentration of the total PAHs bound to PM_2.5 for NW, NE, SE, and SW zones were 519.51 (638.78), 109.16 (169.16), 158.89 (178.40), and 77.65 (89.60) ng/m³ for both wet and dry seasons. The average toxicity equivalence quotient (TEQ) of atmospheric PAHs in PM_2.5 for Benin City was 75.71 ± 70.54 ngm^-3. The incremental lifetime cancer risk for 8-hour TWA exposure obtained for PM_2.5-bound atmospheric PAHs for children (4.45 × 10^-6 and 3.48 × 10^-6) and infants (1.05 × 10^-6 and 8.17 × 10^-7) were to be within the acceptable risk level (10^-6). In contrast, for adults they were not within the acceptable risk level ((3.58 × 10^-5 and 2.80 × 10^-5) for both dry and wet seasons. The authors conclude that the lungs of the people living within the north-west district are likely being damaged and they recommend the implementation of measures to reduce exposure to PM_2.5-bound PAHs in the workplace.