Emissions of particulate matter and polycyclic aromatic hydrocarbons from household coal combustions

Incomplete combustion of household coal is one of the major emission sources of particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs), which have caused serious harmful impacts on the atmospheric environment and human health. To evaluate the effects of coal types and their combustion methods on the PM and PAHs emissions, four different coals, namely bituminous chunk coal, bituminous coal briquette, anthracite coal briquette and semi-coke were respectively combusted in three typical household cooking and heating coal stoves (i.e. updraft stove, downdraft stove and decoupling combustion stove). Based on the experimental results, the toxicity equivalents (TEs) were calculated and compared with the data reported in the literature. With the decoupling combustion stove, the emission factors of particulate matter (EFPM) and polycyclic aromatic hydrocarbons (EFPHAs) were measured to be 0.50 g/kg and 403.2 μg/kg for the bituminous coal briquette, 3.65 g/kg and 989.6 μg/kg for the bituminous chunk coal, 1.08 g/kg and 622.3 μg/kg for the semi-coke and 2.10 g/kg and 148.3 μg/kg for the anthracite coal briquette. Clearly, the bituminous coal briquette combustion produced significantly lower PM and PAHs than combustion of other coal types, except for the EFPAHs of the anthracite coal briquette. With the same bituminous chunk coal combusted, the EFPM and EFPHAs were determined as 3.65 g/kg, 989.6 μg/kg for the decoupling stove, 46.58 g/kg and 16182.3 μg/kg for the updraft stove, and 6.00 g/kg and 11749.4 μg/kg for the downdraft stove, strongly suggesting that the combustion methods have an even bigger impact than fuel type on the emissions of PM and PAHs. Furthermore, the experimental data showed that the decoupling stove burning the bituminous coal briquette produced the lowest PM and PAHs, with the EFPM and EFPHAs being 0.50 g/kg, 403.2 μg/kg, followed by the updraft stove burning the semi-coke (EFPM 1.62 g/kg, EFPHAs 1196.5 μg/kg) and the updraft stove burning the anthracite coal briquette ( EFPM 1.32 g/kg, EPPHAs 66.5 μg/kg). All of these were significantly lower than the data from the updraft stove burning bituminous chunk coals, which were 46.58 g/kg and 16182.3 μg/kg from this study and 0.68-24.3 g/kg and 680-137700 μg/kg reported in the literature. The results indicated that the emissions of PM and PAHs were affected by both the combustion methods and the coal quality characteristics, and the efficient combustion played a greater role in reducing the emissions. The "coal stove matching" technology can make rational, effective and clean utilization of China􀆳s huge reserves of bituminous coal resources. © All Right Reserved.