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Your search keyword '"Ward, Darold E."' showing total 40 results
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40 results on '"Ward, Darold E."'

1. Measurement and modeling of air toxins from smoldering combustion of biomass

Author

McKenzie, Lisa M., Hao, Wei Min, Richards, Geoffrey N., and Ward, Darold E.

Subjects
Biomass -- Research, Organic compounds -- Research, Combustion -- Environmental aspects, Environmental issues, Science and technology
Abstract

The presence of oxygenated organic compounds in condensed smoke of different types of biomass under smoldering, self-sustained smoldering and flaming conditions were analyzed using gas chromatography/mass spectrometry and gas chromatography/flame ionization detection. The results showed that 2-furaldehyde, vinyl acetate, acetol and methanol were the major condensible emissions.

Published
1995

2. Factors affecting methyl chloride emissions from forest biomass combustion

Author

Reinhardt, Timothy E. and Ward, Darold E.

Subjects
Biomass -- Research, Chloromethane -- Research, Combustion -- Environmental aspects, Environmental issues, Science and technology
Abstract

Vegetative biomass burning produces the trace gas chloromethane. The factors which influence methyl chloride emissions from biomass combustion were investigated using regression analysis. The results showed that CH3-Cl emission factors are dependent on combustion efficiency, rate of heat release and fuel chloride level. Combustion conditions also had an effect on the amount of chlorine in fine particle emissions.

Published
1995

3. Trace Gas Measurements in Nascent, Aged and Cloud-processed Smoke from Africa Savanna Fires by Airborne Fourier Transform Infrared Spectroscopy (AFTIR)

Author

Yokelson, Robert J, Bertschi, Isaac T, Christian, Ted J, Hobbs, Peter V, Ward, Darold E, and Hao, Wei Min

Subjects
Environment Pollution
Abstract

We measured stable and reactive trace gases with an airborne Fourier transform infrared spectrometer (AFTIR) on the University of Washington Convair-580 research aircraft in August/September 2000 during the SAFARI 2000 dry season campaign in Southern Africa. The measurements included vertical profiles of C02, CO, H20, and CH4 up to 5.5 km on six occasions above instrumented ground sites and below the TERRA satellite and ER-2 high-flying research aircraft. We also measured the trace gas emissions from 10 African savanna fires. Five of these fires featured extensive ground-based fuel characterization, and two were in the humid savanna ecosystem that accounts for most African biomass burning. The major constituents we detected in nascent CH3OOH, HCHO, CH30H, HCN, NH3, HCOOH, and C2H2. These are the first quantitative measurements of the initial emissions of oxygenated volatile organic compounds (OVOC), NH3, and HCN from African savanna fires. On average, we measured 5.3 g/kg of OVOC and 3.6 g/kg of hydrocarbons (including CH4) in the initial emissions from the fires. Thus, the OVOC will have profound, largely unexplored effects on tropical tropospheric chemistry. The HCN emission factor was only weakly dependent on fire type; the average value (0.53 g/kg) is about 20 times that of a previous recommendation. HCN may be useful as a tracer for savanna fires. Delta O3/Delta CO and Delta CH3COO/Delta CO increased to as much as 9% in <1 h of photochemical processing downwind of fires. Direct measurements showed that cloud processing of smoke greatly reduced CH30H, NH3, CH3COOH, SO2, and NO2 levels, but significantly increased HCHO and NO.

Published
2003
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6. Characteristics of smoke emissions from biomass fires of the Amazon region - BASE-A experiment

Author

Ward, Darold E, Setzer, Alberto W, Kaufman, Yoram J, and Rasmussen, Rei A

Subjects
Environment Pollution
Abstract

The Biomass Burning Airborne and Spaceborne Experiment-Amazonia was designed for study of both aerosol and gaseous emissions from fires using an airborne sampling platform. The emission factors for combustion products from four fires suggest that the proportion of carbon released in the form of CO2 is higher than for fires of logging which has been burned in the western U.S. Combustion efficiency was of the order of 97 percent for the Amazonian test fire and 86-94 percent for deforestation fires. The inorganic content of particles from tropical fires are noted to be different from those of fires in the U.S.

Published
1991

7. Optical properties of aerosol emissions from biomass burning in the tropics, BASE-A

Author

Holben, Brent N, Kaufman, Yoram J, Setzer, Alberto W, Tanre, Didre D, and Ward, Darold E

Subjects
Geophysics
Abstract

Ground-based and airborne measurements of biomass-burning smoke particle optical properties, obtained with a view to aerosol-absorption properties, are presented as a function of time and atmospheric height. The wavelength dependence of the optical thickness can be explained by a log-normal size distribution, with particles' effective radius varying between 0.1 and 0.2 microns. The strong correlation noted between aerosol particle profile and CO profile indicates that smoke particulates constitute a good tracer for emission trace gases from tropical biomass burning.

Published
1991

19. Potential global fire monitoring from EOS-MODIS

Author

Kaufman, Yoram J., primary, Justice, Christopher O., additional, Flynn, Luke P., additional, Kendall, Jackie D., additional, Prins, Elaine M., additional, Giglio, Louis, additional, Ward, Darold E., additional, Menzel, W. Paul, additional, and Setzer, Alberto W., additional

Published
1998
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