Structure fires and toxic fallout: Investigating the exposure hazards through inhalable dust analysis

This study assesses the environmental impact of a structural fire near a Material Collection Facility (MCF) in southwestern India, focusing on the dispersion of PM₂.₅ dispersion and the chemical profiling of inhalable dust particles (<100 µm). Using the HYSPLIT dispersion model in conjunction with Kernel Density Estimation (KDE), the spatial distribution and potential transport pathways of PM₂.₅ were analyzed. KDE results revealed zones of intense particulate accumulation, with density values exceeding 350 arbitrary density units (ADU). These high-density clusters were predominantly located over vulnerable microenvironments, including an old age home, multiple schools, and a special education center, indicating a high risk of localized exposure following the fire event. Inhalable dust collected post-incident was analyzed using Micro-Raman Spectroscopy (MRS), Attenuated Total Reflectance–Fourier Transform Infrared (ATR–FTIR) spectroscopy, and High-Resolution Mass Spectrometry (HRMS). MRS confirmed the presence of soot-bound mineral particles, while ATR–FTIR identified occurrence of fine asbestos, calcite and quartz minerals in combustion residues. HRMS-based non-target screening revealed 16 organic compounds belonging to various classes, including polycyclic aromatic compounds (PACs), plasticizers and their metabolites, surfactants, solvents, and pharmaceutical residues. Molecular docking analysis with CYP4501A2, CYP4503A4, and HSA proteins indicated high binding affinities for PACs, suggesting potential health relevance. The combined application of MRS, ATR–FTIR, and HRMS proved to be effective in detailed multi-scale analysis of particulates resulting from the fire, offering critical insights into their composition and potential biological interactions. • PM 2.5 dispersion analysis indicated the transport of particulates over a Ramsar lake. • MRS technique unveiled the presence of soot-adhered mineral particulates. • 16 compounds belonging to various classes (PACs, PPCP, surfactants, solvents, and plasticisers) were identified. • PACs had the highest binding affinity to CYP4501A2, CYP4503A4 and HSA proteins.