PARTICLE CONCENTRATIONS, GAS-PARTICLE PARTITIONING, AND SPECIES INTERCORRELATIONS FOR POLYCYCLIC AROMATIC-HYDROCARBONS (PAH) EMITTED DURINGBIOMASS BURNING

Eight types of agricultural and forest fuels including 4 cereal crop r esidues and 4 wood fuels were burned in a combustion wind tunnel to si mulate the open burning of biomass. Concentrations for 19 PAH species in particulate matter were found to range between 120 and 4000 mg kg(- 1), representing between 1 and 70% of total PAH emission. Weakly flami ng spreading fires in the cereals were observed to produce higher leve ls of heavier PAH than more robust fires, with greater partitioning of PAH to the particle phase. Individual species concentrations appeared well correlated within groups based primarily on molecular weight, bu t no single species was observed to correlate with all others to serve as an indicator of PAH emission strength. Equilibrium gas-particle pa rtitioning did not appear to be achieved within the 3-5 s residence ti me prior to sampling for sampling temperatures between 32 and 87 degre es C, and in particular for the heavier species emitted from wood fuel pile fires with higher stack gas temperatures and shorter residence t imes. Total PAH emission, particle-phase concentrations, and fraction of PAH on particles were more strongly influenced by burning condition s than by fuel type. Copyright (C) 1996 Elsevier Science Ltd.