Abstract (talk 1): Biomass burning (BB) is a significant and growing source of atmospheric pollution, exacerbated by climate-driven increases in fire frequency and intensity. Burning of anthropogenic materials is also a major concern in developed and developing countries. This presentation synthesizes multidisciplinary evidence from ambient measurements, chemical characterization, and toxicological assays to elucidate the physicochemical and biological impacts of BB aerosols. Field campaigns in Israel identified distinct BB events through nucleation and particle growth, marked by elevated concentrations of Aitken and accumulation mode particles enriched in organic material and transition metals (e.g., Zn, As, Cd). Positive matrix factorization (PMF) attributed these events to anthropogenic biomass burning sources, including wood and charcoal combustion. High-resolution mass spectrometry revealed heavily oxygenated organic compounds, correlating with elevated oxidative potential (OPv) and reactive oxygen species (ROSv) in both acellular (DTT) and cellular (DCF) assays.

In vitro exposures using human lung epithelial (A549) and hepatic (HepG2) cells demonstrated that BB-derived water-soluble PM induces pronounced oxidative stress, inflammation, and DNA damage. These effects were magnified under metabolic stress conditions such as non-alcoholic fatty liver disease (NAFLD), suggesting heightened susceptibility in vulnerable populations. Notably, OPv and ROSv were strongly linked to particle size (especially <0.49 µm), chemical composition, and source factors. Complementary metabolomic analyses and inflammatory biomarker profiling further confirmed BB particles' potential to disrupt redox homeostasis, lipid metabolism, and mitochondrial function. This work underscores the urgent need to refine air quality metrics beyond mass concentration to include source-specific toxicity and to consider the cumulative burden of pollution and comorbidities on public health.