Condensed aromatic carbon (ConAC), often referred to as black carbon (BC), in soils and rivers is primarily derived from the incomplete combustion of biomass, such as wildfires. However, wildfires alone cannot fully explain the observed levels of ConAC in soils and rivers, suggesting that additional sources contribute to its formation. This study aims to assess the role of reactive oxygen species (ROS) in the degradation of lignin as a potential source of non-pyrogenic black carbon, using high-field 800 MHz NMR for detailed structural analysis.