Firefighter exposure to polycyclic aromatic hydrocarbons and black carbon during prescribed burns and wildfires

Abstract

Prescribed burns are valuable tools for landscape management, which reduce wildfire risk in fire-prone ecosystems. However, they generate smoke emissions containing hazardous pollutants such as polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC). Here, PAHs were analyzed in atmospheric particulate matter (PM_2.5) filters in firefighter's personal real-time BC monitors during prescribed burns and wildfires between 2022 and 2024 in Catalonia (NE Spain). The innovative analytical method using gas-chromatography coupled to Q-exactive Orbitrap mass spectrometry (GC-Orbitrap-MS) allows the determination of personal exposure levels of toxic particle-phase PAHs in firefighters across a broad concentration range, and reveals task-specific exposure levels and profiles, with torchers, who ignite the prescribed burns, facing the highest concentrations (mean BC: 69 μg/m³, mean sum of PAHs: 394 ng/m³, mean benzo[a]pyrene (BaP): 56 ng/m³) during shifts, followed by liners, who manage the fire lines, and truck drivers exhibited the lowest exposure concentrations due to their roles being farther from the hotspot (mean BC < 4 μg/m³). A strong correlation between BC and individual PAHs highlights BC's potential as a proxy for PAH exposure. Although exposure times to elevated smoke particles were normally under 4 h during a shift, risk assessment estimations show that torchers' excess lifetime cancer risk (ELCR) safety thresholds. Findings emphasize the need for improved respiratory protection, task-specific safety protocols, and safer ignition methods to reduce health risks. This study highlights potential risks associated with prescribed burns and wildfires, providing critical data to inform firefighter safety in wildfire-prone regions.