Morphology, composition, and mixing state of individual particles emitted from crop residue, wood, and solid waste combustion in a residential stove were analyzed using transmission electron microscopy (TEM). Our study showed that particles from crop residue and apple wood combustion were mainly organic matter (OM) in smoldering phase, whereas soot-OM internally mixed with K in flaming phase. Wild grass combustion in flaming phase released some Cl-rich-OM/soot particles and cardboard combustion released OM and S-rich particles. Interestingly, particles from hardwood (pear wood and bamboo) and softwood (cypress and pine wood) combustion were mainly soot and OM in the flaming phase, respectively. The combustion of foam boxes, rubber tires, and plastic bottles/bags in the flaming phase released large amounts of soot internally mixed with a small amount of OM, whereas the combustion of printed circuit boards and copper-core cables emitted large amounts of OM with Br-rich inclusions. In addition, the printed circuit board combustion released toxic metals containing Pb, Zn, Sn, and Sb. The results are important to document properties of primary particles from combustion sources, which can be used to trace the sources of ambient particles and to know their potential impacts in human health and radiative forcing in the air.

Black carbon (BC), emitted by incomplete combustion of biomass and fossil fuels, can strongly absorb sunlight in the atmosphere (Bond & Bergstrom, 2006). BC can transform electromagnetic energy into thermal energy and heat the atmosphere (Buseck et al., 2014) and is one of the most important aerosol components affecting radiative forcing in the atmosphere (Jacobson, 2001). Moreover, BC can indirectly affect the climate through influencing the albedo and lifetime of clouds, snow, and ice (Flanner et al., 2007;Koch & Del Genio, 2010;Menon et al., 2010). Understanding the optical properties of BC is necessary to estimate its