Ultrafine particle emission physical-chemical characteristics of two residential woody biomass appliances

Two common types of wood (beech and fir) were burned in commercial pellet (11.1 kW) and wood (8.2 kW) stoves following a combustion cycle simulating the behavior of a real-world user. Ultrafine particulate matter (UFP, dp<100 nm) was sampled with three parallel multistage impactors and analyzed for metals, main water soluble ions, anhydrosugars, total carbon, and PAH content. The measurement of the number concentration and size distribution was also performed by a fourth multistage impactor. UFP mass emissions averaged to 34 mg/m3(@13O2, dry, 0°C) for all the tested stove and wood type (fir, beech)combinations except for beech log burning in the wood stove (80 mg/m3@13O2, dry, 0°C). Compositional differences were observed for pellets and wood UFP samples, where high TC levels characterize the wood log combustion and potassium salts are dominant in every pellet sample. Some diagnostic ratios related to PAH isomers and anhydrosugarsare also compiled from experimental data in the present study and compared to literature values proposed for the emission source discrimination for atmospheric aerosol.