2024 Volume 80 Issue 27 Article ID: 24-27007
Pyrogenic organic matter after wildfires becomes more thermally recalcitrance, however, its characteristics vary depending on the type of combustible material and combustion properties. In this study, thermogravimetry differential thermal analysis (TG-DTA) was conducted on burned samples from the Nishinomiya wildfire of 2021 (burned area: 167 ha) to establish conditions for analyzing the characteristics of pyrogenic organic matter in a general ignition loss test. As a result, organic matter that burns at approximately 300 and 400°C in an air atmosphere was confirmed in the unburned samples, while only substances that burn at approximately 400°C were observed in the burned samples, suggesting that cellulose had been burned off. The 𝑅𝑅50 index of thermal recalcitrance was consistent with values obtained in previous studies. Moreover, the TG-DTA was conducted at fixed temperatures of 300 and 400 °C. The ignition loss of the unburned and burnt samples showed little difference at 400 °C and a 20-30% difference at 300 °C, where the characteristics of the pyrogenic organic matter can be indicated even by the general ignition loss test.
