scholarly journals Supplementary material to "Chemical composition, optical properties and radiative forcing efficiency of nascent particulate matter emitted by an aircraft turbofan burning conventional and alternative fuels"

2018 ◽  
Author(s):  
Miriam Elser ◽  
Benjamin T. Brem ◽  
Lukas Durdina ◽  
David Schönenberger ◽  
Frithjof Siegerist ◽  
...  
Keyword(s):  
Optical Properties ◽  
Particulate Matter ◽  
Chemical Composition ◽  
Radiative Forcing ◽  
Alternative Fuels ◽  
Supplementary Material

scholarly journals Chemical composition, optical properties and radiative forcing efficiency of nascent particulate matter emitted by an aircraft turbofan burning conventional and alternative fuels

2018 ◽  
Author(s):  
Miriam Elser ◽  
Benjamin T. Brem ◽  
Lukas Durdina ◽  
David Schönenberger ◽  
Frithjof Siegerist ◽  
...  
Keyword(s):  
Optical Properties ◽  
Particulate Matter ◽  
Chemical Composition ◽  
Radiative Forcing ◽  
Alternative Fuels ◽  
Measurement Data ◽  
Particulate Emissions ◽  
Low Thrust ◽  
Fuel Blends ◽  
Wide Range

Abstract. Aircraft engines are a unique source of carbonaceous aerosols in the upper troposphere. There, these particles can more efficiently interact with solar radiation than at ground. Due to the lack of measurement data, the radiative forcing from aircraft particulate emissions remains uncertain. To better estimate the global radiative effects of aircraft exhaust aerosol, its optical properties need to be comprehensively characterized. In this work we present the link between the chemical composition and the optical properties of the particulate matter (PM) measured at the engine exit plane of a CFM56-7B turbofan. The measurements covered a wide range of power settings (thrust), ranging from ground idle to take-off, using four different fuel blends of conventional Jet A-1 and Hydro-processed Ester and Fatty Acids (HEFA) biofuel. At the two measurement wavelengths (532 and 870 nm) and for all tested fuels, the absorption and scattering coefficients increased with thrust, as did the PM mass. The separation of elemental carbon (EC) and organic carbon (OC) revealed a significant mass fraction of OC (up to 90 %) at low thrust levels, while EC mass dominated at medium and high thrust. The use of HEFA blends induced a significant decrease in the PM mass and the optical coefficients at all thrust levels. The HEFA effect was highest at low thrust levels, where the EC mass was reduced by up to 50–60 %. The variability in the chemical composition of the particles was the main reason for the strong thrust dependency of the single scattering albedo (SSA), which followed the same trend as the OC fraction. Mass absorption coefficients (MAC) were determined from the correlations between aerosol light absorption and EC mass concentration. The obtained MAC values (MAC532 = 7.5 ± 0.3 m2 g−1 and MAC870 = 5.2 ± 0.9 m2 g−1) are in excellent agreement with previous literature values of absorption cross section for freshly generated soot. The Simple Forcing Efficiency (SFE) was used to evaluate the direct radiative effect of aircraft particulate emissions for various ground surfaces. The results indicate that aircraft PM emissions over highly reflective surfaces like snow or ice have a substantial warming effect. The use of the HEFA fuel blends decreased PM emissions, but no changes where observed in terms of EC/OC composition, optical properties and forcing per mass emitted.

scholarly journals Chemical composition and radiative properties of nascent particulate matter emitted by an aircraft turbofan burning conventional and alternative fuels

2019 ◽  
Vol 19 (10) ◽  
pp. 6809-6820 ◽  
Author(s):  
Miriam Elser ◽  
Benjamin Tobias Brem ◽  
Lukas Durdina ◽  
David Schönenberger ◽  
Frithjof Siegerist ◽  
...  
Keyword(s):  
Optical Properties ◽  
Particulate Matter ◽  
Chemical Composition ◽  
Alternative Fuels ◽  
Radiative Properties ◽  
Total Carbon ◽  
Low Thrust ◽  
Scattering Coefficients ◽  
Fuel Blends ◽  
Wide Range

Abstract. Aircraft engines are a unique source of carbonaceous aerosols in the upper troposphere. There, these particles can more efficiently interact with solar radiation than at ground. Due to the lack of measurement data, the radiative forcing from aircraft exhaust aerosol remains uncertain. To better estimate the global radiative effects of aircraft exhaust aerosol, its optical properties need to be comprehensively characterized. In this work we present the link between the chemical composition and the optical properties of the particulate matter (PM) measured at the engine exit plane of a CFM56-7B turbofan. The measurements covered a wide range of power settings (thrust), ranging from ground idle to take-off, using four different fuel blends of conventional Jet A-1 and hydro-processed ester and fatty acids (HEFA) biofuel. At the two measurement wavelengths (532 and 870 nm) and for all tested fuels, the absorption and scattering coefficients increased with thrust, as did the PM mass. The analysis of elemental carbon (EC) and organic carbon (OC) revealed a significant mass fraction of OC (up to 90 %) at low thrust levels, while EC mass dominated at medium and high thrust. The use of HEFA blends induced a significant decrease in the PM mass and the optical coefficients at all thrust levels. The HEFA effect was highest at low thrust levels, where the EC mass was reduced by up to 50 %–60 %. The variability in the chemical composition of the particles was the main reason for the strong thrust dependency of the single scattering albedo (SSA), which followed the same trend as the fraction of OC to total carbon (TC). Mass absorption coefficients (MACs) were determined from the correlations between aerosol light absorption and EC mass concentration. The obtained MAC values (MAC532=7.5±0.3 m2 g−1 and MAC870=5.2±0.9 m2 g−1) are in excellent agreement with previous literature values of absorption cross section for freshly generated soot. While the MAC values were found to be independent of the thrust level and fuel type, the mass scattering coefficients (MSCs) significantly varied with thrust. For cruise conditions we obtained MSC532=4.5±0.4 m2 g−1 and MSC870=0.54±0.04 m2 g−1, which fall within the higher end of MSCs measured for fresh biomass smoke. However, the latter comparison is limited by the strong dependency of MSC on the particles' size, morphology and chemical composition. The use of the HEFA fuel blends significantly decreased PM emissions, but no changes were observed in terms of EC∕OC composition and radiative properties.

Characterization of Emissions From the Use of Alternative Aviation Fuels

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Tak W. Chan ◽  
Wajid A. Chishty ◽  
Pervez Canteenwalla ◽  
David Buote ◽  
Craig R. Davison
Keyword(s):  
Particulate Matter ◽  
Chemical Composition ◽  
Environmental Sustainability ◽  
Alternative Fuels ◽  
Gaseous Emissions ◽  
Fischer Tropsch ◽  
Alternative Aviation Fuels ◽  
Significant Difference ◽  
Particulate Matter Emissions

Alternative fuels for aviation are now a reality. These fuels not only reduce reliance on conventional petroleum-based fuels as the primary propulsion source, but also offer promise for environmental sustainability. While these alternative fuels meet the aviation fuels standards and their overall properties resemble those of the conventional fuel, they are expected to demonstrate different exhaust emissions characteristics because of the inherent variations in their chemical composition resulting from the variations involved in the processing of these fuels. This paper presents the results of back-to-back comparison of emissions characterization tests that were performed using three alternative aviation fuels in a GE CF-700-2D-2 engine core. The fuels used were an unblended synthetic kerosene fuel with aromatics (SKA), an unblended Fischer–Tropsch (FT) synthetic paraffinic kerosene (SPK) and a semisynthetic 50–50 blend of Jet A-1 and hydroprocessed SPK. Results indicate that while there is little dissimilarity in the gaseous emissions profiles from these alternative fuels, there is however a significant difference in the particulate matter emissions from these fuels. These differences are primarily attributed to the variations in the aromatic and hydrogen contents in the fuels with some contributions from the hydrogen-to-carbon ratio of the fuels.

Characterization of Emissions From the Use of Alternative Aviation Fuels

2015 ◽  
Author(s):  
Tak W. Chan ◽  
Wajid A. Chishty ◽  
Pervez Canteenwalla ◽  
David Buote ◽  
Craig R. Davison
Keyword(s):  
Particulate Matter ◽  
Chemical Composition ◽  
Environmental Sustainability ◽  
Alternative Fuels ◽  
Gaseous Emissions ◽  
Fischer Tropsch ◽  
Alternative Aviation Fuels ◽  
Significant Difference ◽  
Particulate Matter Emissions

Alternative fuels for aviation are now a reality. These fuels not only reduce reliance on conventional petroleum-based fuels as the primary propulsion source, but also offer promise for environmental sustainability. While these alternative fuels meet the aviation fuels standards and their overall properties resemble those of the conventional fuel, they are expected to demonstrate different exhaust emissions characteristics because of the inherent variations in their chemical composition resulting from the variations involved in the processing of these fuels. This paper presents the results of back-to-back comparison of emissions characterization tests that were performed using three alternative aviation fuels in a GE CF-700-2D-2 engine core. The fuels used were an unblended synthetic kerosene fuel with aromatics (SKA), an unblended Fischer Tropsch synthetic paraffinic kerosene (SPK) and a semi-synthetic 50-50 blend of Jet A-1 and hydroprocessed SPK. Results indicate that while there is little dissimilarity in the gaseous emissions profiles from these alternative fuels, there is however a significant difference in the particulate matter emissions from these fuels. These differences are primarily attributed to the variations in the aromatic and hydrogen contents in the fuels with some contributions from the hydrogen-to-carbon ratio of the fuels.

scholarly journals Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements

2013 ◽  
Vol 13 (18) ◽  
pp. 9337-9350 ◽  
Author(s):  
A. Cazorla ◽  
R. Bahadur ◽  
K. J. Suski ◽  
J. F. Cahill ◽  
D. Chand ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Radiative Forcing ◽  
Wavelength Dependence ◽  
Optical Measurements ◽  
Carbonaceous Aerosols ◽  
Angstrom Exponent ◽  
Ångström Exponent ◽  
Ångstrom Exponent

Abstract. Estimating the aerosol contribution to the global or regional radiative forcing can take advantage of the relationship between the spectral aerosol optical properties and the size and chemical composition of aerosol. Long term global optical measurements from observational networks or satellites can be used in such studies. Using in-situ chemical mixing state measurements can help us to constrain the limitations of such estimates. In this study, the Absorption Ångström Exponent (AAE) and the Scattering Ångström Exponent (SAE) derived from 10 operational AERONET sites in California are combined for deducing chemical speciation based on wavelength dependence of the optical properties. In addition, in-situ optical properties and single particle chemical composition measured during three aircraft field campaigns in California between 2010 and 2011 are combined in order to validate the methodology used for the estimates of aerosol chemistry using spectral optical properties. Results from this study indicate a dominance of mixed types in the classification leading to an underestimation of the primary sources, however secondary sources are better classified. The distinction between carbonaceous aerosols from fossil fuel and biomass burning origins is not clear, since their optical properties are similar. On the other hand, knowledge of the aerosol sources in California from chemical studies help to identify other misclassification such as the dust contribution.

scholarly journals Optical Properties, Chemical Composition and the Toxicological Potential of Urban Particulate Matter

2017 ◽  
Vol 17 (6) ◽  
pp. 1515-1526 ◽  
Author(s):  
Máté Pintér ◽  
Zoltán Bozóki ◽  
László Manczinger ◽  
Csaba Vágvölgyi ◽  
Eszter Horváth ◽  
...  
Keyword(s):  
Optical Properties ◽  
Particulate Matter ◽  
Chemical Composition ◽  
Urban Particulate Matter

scholarly journals Optical-chemical relationships for carbonaceous aerosols observed at Jeju Island, Korea with a 3-laser photoacoustic spectrometer

2010 ◽  
Vol 10 (4) ◽  
pp. 9369-9389 ◽  
Author(s):  
B. A. Flowers ◽  
M. K. Dubey ◽  
C. Mazzoleni ◽  
E. A. Stone ◽  
J. J.. Schauer ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Radiative Forcing ◽  
Optical Model ◽  
Index Of Refraction ◽  
Enhanced Absorption ◽  
Aerosol Absorption ◽  
Photoacoustic Spectrometer ◽  
Wide Range ◽  
Pollution Plumes

Abstract. Transport of aerosols in pollution plumes from the mainland Asian continent was observed in situ at Jeju, South Korea during the Cheju Asian Brown Cloud Plume-Asian Monsoon Experiment (CAPMEX) field campaign throughout August and September 2008 using a 3-laser photoacoustic spectrometer. Transport of mixed sulfate, carbonaceous, and nitrate aerosols from various Asian pollution plumes to Jeju accounted for 76% of the deployment days, showing large variations in their measured chemical and optical properties. Our analysis of eight distinct episodes, spanning a wide range of chemical composition, optical properties, and source regions, reveals that at episodes with higher OC/SO2−4 and NO−3/SO2−4 composition ratios exhibit lower single scatter albedo at shorter wavelengths (ω405); significantly lower [ω405meas = 0.79±0.06, ω405calc = 0.86±0.01] than predicted by an optical model that assumes constant complex index of refraction with wavelength (an optical model of soot). We attribute this discrepancy to enhanced absorption by organic material. Organic carbon absorption accounts for up to 50% of the measured aerosol absorption at 405 nm for the high OC/SO2−4 episode. Coatings of elemental carbon aerosol cores are hypothesized to increase absorption by factors up to 6 at visible wavelengths. Carbonaceous aerosol absorption can alter global radiative forcing estimates substantially, underscoring the need to understand and predict chemical composition effects on optical properties.

scholarly journals Relating aerosol absorption due to soot, organic carbon, and dust to emission sources determined from in-situ chemical measurements

2013 ◽  
Vol 13 (2) ◽  
pp. 3451-3483 ◽  
Author(s):  
A. Cazorla ◽  
R. Bahadur ◽  
K. J. Suski ◽  
J. F. Cahill ◽  
D. Chand ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Radiative Forcing ◽  
Optical Measurements ◽  
Carbonaceous Aerosols ◽  
Aerosol Composition ◽  
Angstrom Exponent ◽  
Ångström Exponent ◽  
Ångstrom Exponent

Abstract. Estimating the aerosol contribution to the global or regional radiative forcing can take advantage of the relationship between the spectral aerosol optical properties and the size and chemical composition of aerosol. Long term global optical measurements from observational networks or satellites can be used in such studies. Using in-situ chemical mixing state measurements can help us to constrain the limitations of such estimates. In this study, the Absorption Ångström Exponent (AAE) and the Scattering Ångström Exponent (SAE) derived from 10 operational AERONET sites in California are combined for deducing chemical speciation based on wavelength dependence of the optical properties. In addition, in-situ optical properties and single particle chemical composition measured during three aircraft field campaigns in California between 2010 and 2011 are combined in order to validate the methodology used for the estimates of aerosol composition using spectral optical properties. Results from this study indicate a dominance of mixed types in the classification leading to an underestimation of the primary sources, however secondary sources are better classified. The distinction between carbonaceous aerosols from fossil fuel and biomass burning origins is not clear, since their optical properties are similar. On the other hand, knowledge of the aerosol sources in California from chemical studies help to identify other misclassification such as the dust contribution.

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