Phase distribution and probabilistic risk assessment of polycyclic aromatic hydrocarbons in indoor air of coffee shops at Zahedan, Iran

Polycyclic aromatic hydrocarbons (PAHs) are a class of hydrocarbons, some of which are established human carcinogens. Human exposure to these chemicals is complex and originates from both indoor and outdoor sources. This study measured the concentration of PAHs in the gaseous and particulate phases during the cold months of 2022 using XAD-2 sorbent tubes and Polytetrafluoroethylene (PTFE) filters in the indoor air of coffee shops in Zahedan, Iran (n=23). The average concentrations of particulate-bound PAHs and gaseous PAHs were 13,411.86 ± 6,517.24 ng/m³ and 6,432.76 ± 4,311.72 ng/m³, respectively. Source apportionment analyses indicated that the primary sources of PAHs in coffee shops were fossil fuel combustion and environmental tobacco smoke (ETS), commonly referred to as second and third-hand smoke. The lifetime cancer risk (LTCR) of inhaled PAHs was calculated using the Monte Carlo simulation method. The mean LTCR for adults and children from inhaling these substances were 9.43×10 - 6 ± 5.06 ×10 - 6 and 5.34×10 - 6 ± 2.87 ×10 - 6, respectively. The hazard quotient (HQ) of PAHs exceeded 1. These findings highlight the need to reduce PAHs exposure in public spaces through proper health warning labels and regulated indoor smoking policies.