Occupational exposure as a firefighter is a complex activity that continuously exposes subjects to several health hazards including fire emissions during firefighting. Firefighters are exposed to polycyclic aromatic hydrocarbons (PAHs), known as toxic, mutagenic, and carcinogenic compounds, by inhalation, dermal contact, and ingestion. In this work, a literature overview of firefighters’ dermal exposure to PAHs after firefighting and data retrieved from skin in vitro/in vivo studies related to their dermal absorption, bioavailability, and associated toxicological and carcinogenic effects are reviewed. The evidence demonstrates the contamination of firefighters’ skin with PAHs, mainly on the neck (2.23–62.50 ng/cm²), wrists (0.37–8.30 ng/cm²), face (2.50–4.82 ng/cm²), and hands (1.59–4.69 ng/cm²). Concentrations of possible/probable carcinogens (0.82–33.69 ng/cm²), including benzopyrene isomers, were found on firefighters’ skin. PAHs penetrate the skin tissues, even at low concentrations, by absorption and/or diffusion, and are locally metabolized and distributed by the blood route to other tissues/organs. Lighter PAHs presented increased dermal permeabilities and absorption rates than heavier compounds. Topical PAHs activate the aryl hydrocarbon receptor and promote the enzymatic generation of reactive intermediates that may cause protein and/or DNA adducts. Future research should include in vitro/in vivo assays to perform a more realistic health risk assessment and to explore the contribution of dermal exposure to PAHs total internal dose.

Firefighters’ occupational activity causes cancer, and the characterization of exposure during firefighting activities remains limited. This work characterizes, for the first time, firefighters’ exposure to (coarse/fine/ultrafine) particulate matter (PM) bound polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s during prescribed fires, Fire 1 and Fire 2 (210 min). An impactor collected 14 PM fractions, the PM levels were determined by gravimetry, and the PM-bound PAHs and metal(loid)s were determined by chromatographic and spectroscopic methodologies, respectively. Firefighters were exposed to a total PM level of 1408.3 and 342.5 µg/m³ in Fire 1 and Fire 2, respectively; fine/ultrafine PM represented more than 90% of total PM. Total PM-bound PAHs (3260.2 ng/m³ in Fire 1; 412.1 ng/m³ in Fire 2) and metal(loid)s (660.8 ng/m³ versus 262.2 ng/m³), distributed between fine/ultrafine PM, contained 4.57–24.5% and 11.7–12.6% of (possible/probable) carcinogenic PAHs and metal(loid)s, respectively. Firefighters’ exposure to PM, PAHs, and metal(loid)s were below available occupational limits. The estimated carcinogenic risks associated with the inhalation of PM-bound PAHs (3.78 × 10⁻⁹ − 1.74 × 10⁻⁶) and metal(loid)s (1.50 × 10⁻² − 2.37 × 10⁻²) were, respectively, below and 150–237 times higher than the acceptable risk level defined by the USEPA during 210 min of firefighting activity and assuming a 40-year career as a firefighter. Additional studies need to (1) explore exposure to (coarse/fine/ultrafine) PM, (2) assess health risks, (3) identify intervention needs, and (4) support regulatory agencies recommending mitigation procedures to reduce the impact of fire effluents on firefighters.

Fire emissions aggravate air pollution by releasing several hazardous pollutants, including respirable particulate matter (PM). Evidence on fires contribution to fine and ultrafine PM is scarce, principally in real fire scenarios. This study presents the first morphological and elemental composition of fine (PM_2.5, PM_156nm) and ultrafine (PM_50.4nm, PM_30.8nm, PM_14.9nm) fractions of PM released during three controlled structure (CSF) and two prescribed forest (PFF) fires. Total median PM levels were 9 times higher in CSF emissions than in PFF [11.13 (1.245-228.5) mg/m³versus 1.232 (0.5458-1.920) mg/m³), with fine PM being 13 and 3 times higher than ultrafine PM in CSF and PFF, respectively (p > 0.05). The morphological analysis revealed the prevalence of organic matter in fine/ultrafine PM, with several particles of bright contrast with distinct shapes and sizes, which were more prominent in PFF. The electron dispersive spectroscopy and elemental mapping analysis suggested the presence of sulphates, carbonates, and chlorides of sodium, magnesium, potassium, and calcium (biomass combustion), and stainless-steel particles associated with handling of heavy machinery in PFF. Also, particles of PbCl₂ and PbO (combustion of paints/solder) were observed in CSF. Zn, Cu, Cr, and Ni, as well as Co (in PFF), and Pb (in CSF) were the predominant elements in fire generated PM. Toxic and (possible/probable) carcinogenic elements represented up to 29.3 % and 33.1 % of fine and ultrafine fire generated PM, respectively. This work advances the knowledge on fire-generated PM highlighting the need for further studies on fire chemistry, PM behaviour, and realistic huma exposure and health risk assessments.