Chemical composition and mixing state of elemental carbon-containing particles from solid fuel combustion
Yajing Kong, Qiyuan Wang, Li Li, Yang Zhang, Jie Tian, Nan Ma, Yaqing Zhou, Huikun Liu, Jiawen Liu, Weikang Ran, Jiarui Liu, Chongshu Zhu, Yongming Han, Junji Cao
Abstract
Abstract Elemental carbon (EC), predominantly produced by solid fuel combustion, significantly influences both climate and public health. However, the physicochemical properties of EC-containing particles immediately after emission remain inadequately understood. This study investigates the chemical composition, size distribution, and mixing state of EC-containing particles from five solid fuels: wheat, corn, rice straw, bituminous coal, and anthracite. Using a single-particle aerosol mass spectrometer (SPAMS), we identified seven distinct EC-containing particle types. Our results show that biomass burning primarily produces EC-containing particles obviously coated with organic carbon (EC-OC) and organic nitrogen (EC-CN), with sizes concentrated between 0.4 and 1.0 μm. In contrast, bituminous coal emissions are dominated by sodium-rich EC-containing particles (EC-Na), while anthracite combustion predominantly produces particles coated with sulfate or nitrate (EC-NS). Bituminous coal particles are generally smaller ( < 0.4 μm), likely due to higher volatile content and rapid pyrolysis. The mixing states of EC-containing particles varied markedly. Sulfate ( 97 HSO 4 − ) was strongly associated with EC-OC and EC-Na particles, resulting in a highly mixing state. Levoglucosan ( 59 C 2 H 3 O 2 − ) showed distinct patterns between biomass and coal emissions. These findings provide critical insights into the physicochemical properties of freshly emitted EC-containing aerosols, offering valuable references for atmospheric particle analysis and emission characterization.