Emission Characteristics of IVOCs from the Combustion of Residential Solid Fuels and the Impact of Burning Temperature

: Intermediate-volatility organic compounds (IVOCs) are important precursors of secondary organic aerosols that have received much recent attention; however, there is a lack of emission data for IVOCs from combustion sources, especially for residential solid fuel combustion. In this study, two bituminous coals with different geological maturity (XZ and LW) and two biomass types (rice stalk and pinewood) were tested at seven temperature points (300-900℃ with an interval of 100℃) using a quartz tube furnace together with a dilution sampling system. The results showed that the averaged emission factor for IVOCs from biomass combustion[(483±182) mg·kg-1] was 2.5 times higher than that of bituminous coal combustion (190±108) mg·kg-1. The remaining unresolved complex mixture (UCM) dominated the IVOC content for both biomass and coal combustions (81%±11% and 68%±6%, respectively). The fraction of normal and branched alkanes for biomass combustions was lower than for coal combustion, while the fraction of aromatics was higher. The effect of temperature on the emission of IVOCs and their composition was significantly different between the two types of fuel. The emission factor for IVOCs from coal (using LW as an example) at 500℃[(340±113) mg·kg-1] was 5.4 times higher than at 900℃[(63±15) mg·kg-1], while two comparable peaks are observed at 400-500℃ and 800-900℃. As the combustion temperature increased, the proportion of aromatic hydrocarbons in pinewood IVOCs increased from 1% to 29%, while the remaining UCM decreased from 92% to 61%. However, there was little variation for coal combustion. The effects of fuel type and temperature on the emission of IVOCs were further explained with respect to the modified combustion efficiency (MCE).