Characterization of carbonaceous compounds emitted from Indonesian surface and sub surface peat burning

Abstract Indonesia has been experiencing an annually reoccurring forest fire events over the peatlands in eastern Sumatera and western Kalimantan and the impacts on the air pollution episodes in the surrounding countries gained international concerns. The most notable events were in 1997 and 2015 which caused significant losses both on human health and economy in the region. Fires in peat layers could spread radially due to peat structure and emitted substantial amount of aerosols containing carbonaceous compounds, including BC/EC and OC. In this study, peat samples from different levels of depth were collected from western part of Kalimantan and were burned in a combustion chamber received from Kyoto University. Particulate (PM2.5) samples from burning experiments were collected and the carbonaceous components (i.e. BC/EC and OC) were also analyzed, respectively. The results showed that average concentration of PM2.5 emitted from the combustion of the surface peat (SF) samples was 7,467 ± 3,976 μg/m³. while the corresponding value for the subsurface (SSF) was 5,693 ± 2,137 μg/m³. In average, EC and OC compositions were 1.9% and 70% to the total of PM2.5 concentrations, respectively. Emission factors (EFs, in g/kg) were estimated for PM2.5, EC, and OC for SF samples of 4.51 ± 0.42, 0.21 ± 0.17, and 3.77 ± 0.82, respectively. The associated EFs for SSF samples were 4.53 ± 1.67, 0.1 ± 0.09, and 1.82 ± 0.43 g/kg, respectively. The results may substantially contribute to fill in the gaps of the availability of EFs for both SF and SFF peat fires in the country to improve the existing PM emission database.