LAUSR

Abstract Chemical profiles from burning of raw biomass materials (i.e., maize straw, wheat straw and wood branch) and their processed products (i.e., briquette and charcoal) were determined with a customized cleaning stove in a combustion chamber. Inorganic species such as water-soluble ions and elements, and carbonaceous fractions including saccharide and polycyclic aromatic hydrocarbons (PAHs) in fine particulate matter (PM2.5) were quantified. Organic carbon (OC) was the highest fraction with a mass contribution to PM2.5 ranging from 17.65 ± 0.15% to 40.17 ± 3.83%. Potassium (K+) and chloride (Cl−) were the two most abundant water-soluble ions (4.31 ± 1.57% and 3.05 ± 1.29%, respectively). Most elements (e.g., heavy metals) had relatively low fractions (  briquette > charcoal. In comparison, charcoal burning had lower fractions of the organics since most volatile matters and moisture had been removed during carbonization. In addition, the similarities of chemical profiles from different bio-fuels burning were assessed by calculating the coefficient of divergence (CD) and their correlations. Relatively low CD (0.21–0.36) and high correlation (R > 0.97) suggest that the chemical profiles from straw and their briquettes were similar. However, the profiles from charcoal burning showed significant differences between their corresponding raw fuels (CDs = 0.26–0.47, R = 0.69–0.99) and also large variations from each other (CDs = 0.40–0.49, R