Showing papers by "Robert J. Yokelson published in 2008"

The tropical forest and fire emissions experiment: laboratory fire measurements and synthesis of campaign data

Abstract: As part of the Tropical Forest and Fire Emissions Experiment (TROFFEE), tropical forest fuels were burned in a large, biomass-fire simulation facility and the smoke was characterized with open-path Fourier transform infrared spectroscopy (FTIR), proton-transfer reaction mass spec- trometry (PTR-MS), gas chromatography (GC), GC/PTR- MS, and filter sampling of the particles. In most cases, about one-third of the fuel chlorine ended up in the parti- cles and about one-half remained in the ash. About 50% of the mass of non-methane organic compounds (NMOC) emitted by these fires could be identified with the available instrumentation. The lab fire emission factors (EF, g com- pound emitted per kg dry fuel burned) were coupled with EF obtained during the TROFFEE airborne and ground-based field campaigns. This revealed several types of EF depen- dence on parameters such as the ratio of flaming to smol- dering combustion and fuel characteristics. The synthesis of data from the different TROFFEE platforms was also used to derive EF for all the measured species for both primary deforestation fires and pasture maintenance fires - the two main types of biomass burning in the Amazon. Many of the EF are larger than those in widely-used earlier work. This is mostly due to the inclusion of newly-available, large EF for the initially-unlofted smoldering emissions from resid- ual logs in pastures and the assumption that these emissions make a significant contribution ( 40%) to the total emissions from pasture fires. The TROFFEE EF for particles with aero- dynamic diameter <2.5 microns (EFPM2.5) is 14.8 g/kg for primary deforestation fires and 18.7 g/kg for pasture main- tenance fires. These EFPM 2.5 are significantly larger than a previous recommendation (9.1 g/kg) and lead to an estimated pyrogenic primary PM2.5 source for the Amazon that is 84% larger. New regional budgets for biogenic and pyrogenic emissions were roughly estimated. Coupled with an estimate of secondary aerosol formation in the Amazon and source ap- portionment studies, the regional budgets suggest that 5% of the total mass of the regionally generated NMOC end up as secondary organic aerosol within the Amazonian bound- ary layer within 1-3 days. New global budgets confirm that biogenic emissions and biomass burning are the two largest global sources of NMOC with an estimated production of ap- proximately 1000 (770-1400) and 500 (250-630) Tg/yr, re- spectively. It follows that plants and fires may also be the two main global sources of secondary organic aerosol. A limited set of emission ratios (ER) is given for sugar cane burning, which may help estimate the air quality impacts of burning this major crop, which is often grown in densely populated areas.

Corrigendum to "The tropical forest and fire emissions experiment: laboratory fire measurements and synthesis of campaign data" published in Atmos. Chem. Phys., 8, 3509–3527, 2008

Abstract: Atmos. Chem. Phys., 8, 4497, 2008 www.atmos-chem-phys.net/8/4497/2008/ © Author(s) 2008. This work is distributed under the Creative Commons Attribution 3.0 License. Atmospheric Chemistry and Physics Corrigendum to “The tropical forest and fire emissions experiment: laboratory fire measurements and synthesis of campaign data” published in Atmos. Chem. Phys., 8, 3509–3527, 2008 R. J. Yokelson 1 , T. J. Christian 1 , T. G. Karl 2 , and A. Guenther 2 1 University 2 National of Montana, Department of Chemistry, Missoula, MT, USA Center for Atmospheric Research, Boulder, CO, USA Erroneously Fig. 2 in the published article includes panel (b) twice. Below the correct figure with panel (a) and (b) is shown. a) Air Lab Ground EFCH 4 (g/kg) MCE b) Air-FTIR Lab-FTIR Ground Lab-PTR EFCH 3 OH (g/kg) MCE Fig. 2. Presentation of all the emission factors measured dur- ing TROFFEE from ground-based, airborne, and laboratory plat- forms for CH 4 (a) and CH 3 OH (b). Despite differences in fu- els between the experiments, these compounds show a consistent trend of increasing emissions with decreasing MCE indicating fuel- independent production largely by smoldering combustion. There is also a large range in the EF observed (factor of ∼20). Correspondence to: R. J. Yokelson (bob.yokelson@umontana.edu) Published by Copernicus Publications on behalf of the European Geosciences Union.