Work

Airborne Polycyclic Aromatic Hydrocarbons (PAHs) in 20 Homes Several Months After the 2023 Maui Wildfires

Year: 2026

Type: preprint

Abstract: Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with adverse health outcomes, including cancer. PAHs are emitted by wildfires and may persist in indoor environments following smoke events. To better understand post-wildfire PAH persistence inside residences, we sampled for 16 airborne PAHs at 20 homes in Lāhainā, Hawaiʻi, 5-7 months after the 2023 Maui wildfires, both before and after deploying an additional air purifier on top of existing indoor filtration and purification systems. Additionally, we surveyed building occupants about pollution-relevant behaviors. Concentrations of all indoor airborne PAHs fell below risk-based screening levels. Estimated cumulative cancer risks and hazard indices were all below 1 × 10-6 and 1, respectively. We found higher concentrations of low-molecular-weight PAHs than highmolecular-weight PAHs. The results of source attribution using indoor/outdoor ratios, principal component analysis, and diagnostic ratios are somewhat equivocal, but we could not clearly identify a biomass-combustion-related source of the indoor airborne PAHs. We found little association between self-reported occupant behaviors and PAH levels, and we found no significant effect of the air purifier on indoor PAH concentraties. These results suggest that there was not substantial fire-related airborne PAH contamination inside local residences several months after a major wildfire event.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.15010848/v1