| Oxygenated organic compounds in condensed ({dollar}-{dollar}45{dollar}spcirc{dollar}C) smoke of 29 bench-scale and five combustion chamber fires (smoldering, self-sustained smoldering and flaming conditions) of ponderosa pine fuels are identified and quantified by gas chromatography/mass spectrometry. Both the bench-scale and combustion chamber fires are reasonably reproducible and give similar emissions. The major condensible emissions are acetic acid, vinyl acetate, acetol and methanol. The emissions depend primarily on fuel chemistry and physical parameters of the fuel and fire and secondarily on combustion efficiency. Molar ratios of individual compound emissions to CO are calculated, and exposure levels to these compounds for wildland firefighters are estimated. Of the compounds measured, none is projected to exceed a toxic level, except for 2-furaldehyde and vinyl acetate, which are suspected carcinogens.; The concentrations of chlorine (Cl) and bromine (Br) in fuel samples collected from Zambian savannas, Brazilian primary and secondary forests, and temperate forests in Oregon were determined by ion chromatography. Wood has significantly less Cl and Br than other classes of biomass and tropical wood has 50-100 times more Cl than temperate wood. Zambian grass has the most Cl and the highest Cl:Br ratio. Duff and humus from the Oregon coast had the most Br and the lowest Cl:Br ratio. Gradients of Cl and Br exist for vegetation over a transect from western to eastern Oregon, with the highest concentrations near the coast.; A feasibility study has been performed to quantify methyl chloride (CH{dollar}sb3{dollar}Cl), methyl bromide (CH{dollar}sb3{dollar}Br), and methyl iodide (CH{dollar}sb3{dollar}I) emissions from 32 bench-scale fires of temperate forest fuels by gas chromatography/electron capture detection. Adsorption and desorption of smoke from Tenax-GR/Graphpac traps resulted in chromatographic peak broadening, with co-elution of oxygenated organics. It is tentatively concluded that a secondary low temperature process occurring on the char results in most CH{dollar}sb3{dollar}Cl and CH{dollar}sb3{dollar}Br emissions. Methyl chloride and CH{dollar}sb3{dollar}Br emissions maximize at 250{dollar}spcirc{dollar}C and 350{dollar}spcirc{dollar}C respectively. Methyl chloride and CH{dollar}sb3{dollar}Br emissions depend primarily on fuel Cl and Br content, increasing with increasing Cl and Br content and secondarily on combustion efficiency, increasing as combustion efficiency decreases. Predictive models for CH{dollar}sb3{dollar}Cl and CH{dollar}sb3{dollar}Br emissions from biomass fires are presented. |
