Human exposure to polycyclic aromatic hydrocarbons in the atmosphere of an agricultural area of central Chile and inhalation cancer risk assessments

Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances prone to long-range atmospheric transport. Even in low concentrations, environmental exposure to PAHs can impact human health. In this study we aimed to i) investigate the occurrence of 15 polycyclic aromatic hydrocarbons (∑15PAHs), from August 2016 to January 2018, in the atmosphere of Molina, using polyurethane foam disks (PAS-PUF) in central Chile; and ii) perform deterministic and probabilistic (using Monte Carlo simulations) inhalation cancer risk assessments. Gas chromatography and tandem quadrupole mass spectrometry (GC- MS/MS) measured target PAHs. Results showed ∑15PAHs ranging from 2 ng m-3 to 108 ng m-3, with four-ring PAHs as the prevalent compounds, including phenanthrene (44%) and fluoranthene (24%). Winter season showed the highest PAH levels (increasing factor up to ∼8 times). PAHs diagnostic ratios showed the prevalence of pyrogenic combustion (winter) and petrogenic combustion (summer). Lifetime cancer risk assessments, using BaP-eq values, indicated an increased cancer risk for the exposed population considering different risk assessment approaches. Younger individuals were the most affected by an increased cancer risk at all sampling sites. The Monte Carlo probabilistic assessment indicated that infants and toddlers could be exposed to PAH air concentrations exceeding the cancer risk threshold in over 94% of the simulations. The coldest months in the studied region are critical for human exposure and health risk due to intense wood combustion. Indoor air can be even more relevant due to the chronic inhalation of the smoke and associated chemicals.