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

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.