Potential Health Risks for Long-Term Stays in Underground Parking Garages: Implications of Polycyclic Aromatic Hydrocarbons in Surface Dust

Surface dust in urban environments is an important carrier and potential source of polycyclic aromatic hydrocarbons (PAHs). However, information regarding PAHs in underground parking garage (UPG) surface dust is still limited. In the present study, a total of 30 surface dust samples were collected from UPGs in apartment communities to assess the content, potential health risks to residents and sources of PAHs. The results showed that the total PAH content in the surface dust in the UPGs ranged from 636.27 to 25448.62 μg/kg, with a mean content of 4097.73 μg/kg. The distribution pattern of PAHs based on ring number exhibited the following order: 2–3 > 5–6 > 4 rings. All these surface dust samples were contaminated with PAHs, and 80% were heavily contaminated (ΣPAH > 1000 μg/kg). Health risk assessment revealed that the mean total carcinogenic risk (TCR) for children and adults was 1.33 × 10⁻⁶ and 1.01 × 10⁻⁶, respectively, indicating that residents suffered acceptable carcinogenic risk. The diagnostic ratios and positive matrix factorization results indicate that pyrogenesis was the primary source of PAHs in UPG surface dust, with diesel combustion, gasoline combustion, vehicular emission, and coal combustion contributing 8.2%, 42.8%, 27.9%, and 21.1%, respectively. These results indicate that effective measures should be implemented to protect local workers and residents from carcinogenic effects.