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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Suggested Citation:"References." National Academies of Sciences, Engineering, and Medicine. 2019. ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report. Washington, DC: The National Academies Press. doi: 10.17226/25548.
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Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 65 References Reference 1 PM Characteristics of Low NOx Combustor Burning Biodiesel and its Blends with Kerosene Abstract PM emissions from gas turbine engines have increasing attention due to their impact on global climate change, human health and local air quality. Most of the existing data for particle size distribution in aero engines is for diffusion or rich/lean type combustors where the rich zones generate solid nano particle carbon emissions. This work investigates well mixed lean low NOx combustion where mixing is good and generation of solid carbon particulate emissions should be very low. This work investigated the particulate number concentrations and size distributions of exhaust gases emitted from a radial swirler based low NOx gas turbine combustor. The tests were conducted using a radial swirler industrial low NOx gas turbine combustor under atmospheric pressure and 600K at reference Mach number of 0.017 and 0.023. A baseline of natural gas combustion was compared with a waste rape seed cooking oil methyl ester biodiesel (WME), its blend with kerosene B20, B50 and pure kerosene. The particulate emissions were compared as a function of the lean well mixed primary zone equivalence ratio. A scanning mobility particle sizer (SMPS) with a Nano-Differential Mobility Analyzer (NDMA) was used to determine the number and concentration and size distribution of aerosols. The results showed that all WME particulates showed unimodal distribution characteristics with peak particle number at around 20nm. Conversion of the number distribution to mass showed very low mass emissions of around 1 mg/kgfuel. Modern low NOx engines such as the Trent 970-84 has carbon mass emissions of 9 mg/kgfuel based on the ICAO FOA-3 procedures. Thus, it is not unreasonable that in much lower NOx combustor designs the solid mass emissions will be lower than in current low NOx engines. Comparison is also made with particulate emissions from a diffusion flame APU gas turbine and much higher particle number emissions were demonstrated. Authors Altaher, M.A., Andrews, G.E., and Li, H. Source Proceedings of ASME Turbo Expo 2013: Turbine Technical Conference and Exposition GT2013. San Antonio, Texas, USA Publication Date June 3-7, 2013

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 66 Reference 2 Alternative Aviation Fuel Experiment (AAFEX) Abstract The rising cost of oil coupled with the need to reduce pollution and dependence on foreign suppliers has spurred great interest and activity in developing alternative aviation fuels. Although a variety of fuels have been produced that have similar properties to standard Jet A, detailed studies are required to ascertain the exact impacts of the fuels on engine operation and exhaust composition. In response to this need, NASA acquired and burned a variety of alternative aviation fuel mixtures in the Dryden Flight Research Center DC-8 to assess changes in the aircraft s CFM-56 engine performance and emission parameters relative to operation with standard JP-8. This Alternative Aviation Fuel Experiment, or AAFEX, was conducted at NASA Dryden s Aircraft Operations Facility in Palmdale, California, from January 19 to February 3, 2009 and specifically sought to establish fuel matrix effects on: 1) engine and exhaust gas temperatures and compressor speeds; 2) engine and APU gas phase and particle emissions and characteristics; and 3) volatile aerosol formation in aging exhaust plumes. Authors Anderson, B.E., et al. Source NASA Project Report NSAS/TMI2011I217059 Publication Date February 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 67 Reference 3 Alternative Fuel Effects on Contrails & Cruise Emissions (ACCESS-2) Flight Experiment Abstract Although the emission performance of gas turbine engines burning renewable aviation fuels have been thoroughly documented in recent ground-based studies, there is still great uncertainty regarding how the fuels effect aircraft exhaust composition and contrail formation at cruise altitudes. To fill this information gap, the NASA Aeronautics Research Mission Directorate sponsored the ACCESS flight series to make detailed measurements of trace gases, aerosols and ice particles in the near-field behind the NASA DC-8 aircraft as it burned either standard petroleum-based fuel of varying sulfur content or a 50:50 blend of standard fuel and a HEFA jet fuel produced from Camelina plant oil. ACCESS 1, conducted in spring 2013 near Palmdale CA, focused on refining flight plans and sampling techniques and used the instrumented NASA Langley HU-25 aircraft to document DC-8 emissions and contrails on five separate flights of approx.2 hour duration. ACCESS 2, conducted from Palmdale in May 2014, engaged partners from the Deutsches Zentrum fuer Luft- und Raumfahrt and National Research Council-Canada to provide additional scientific expertise and sampling aircraft (Falcon 20 and CT-133, respectively) with more extensive trace gas, particle, or air motion measurement capability. Eight, muliti-aircraft research flights of 2 to 4 hour duration were conducted to document the emissions and contrail properties of the DC-8 as it 1) burned low-sulfur Jet A, high sulfur Jet A or low-sulfur Jet A/HEFA blend, 2) flew at altitudes between 6 and 11 km, and 3) operated its engines at three different fuel flow rates. This presentation further describes the ACCESS flight experiments, examines fuel type and thrust setting impacts on engine emissions, and compares cruise- altitude observations with similar data acquired in ground tests. Authors Anderson, B. Source Langley Research Center, ACCESS Science and Implementation Teams Publication Date January 9, 2015

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 68 Reference 4 ASTM D1655-16a, Standard Specification for Aviation Turbine Fuels Abstract This specification covers the use of purchasing agencies in formulating specifications for purchases of aviation turbine fuel under contract. This specification defines the minimum property requirements for Jet A and Jet A-1 aviation turbine fuel and lists acceptable additives for use in civil operated engines and aircrafts. Specification D1655 is directed at civil applications, and maintained as such, but may be adopted for military, government or other specialized uses. Authors ASTM International Source ASTM International. West Conshohocken, PA Publication Date April 1, 2016

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 69 Reference 5 ASTM D7566-16b, Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons Abstract Appendix Section X1.2 Significance and Use of ASTM D1655 was recently modified via D02 (17-01) Item 046 to adopt wording that is more general in nature and better reflects the true intent of the subcommittee. To the extent possible, Subcommittee J attempts to align D1655 and D7566. The identical changes are proposed herein for D7566. Authors ASTM International Source ASTM International. West Conshohocken, PA Publication Date July 1, 2016

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 70 Reference 6 Reductions in Aircraft Particulate Emissions due to the use of Fischer–Tropsch Fuels Abstract The use of alternative fuels for aviation is likely to increase due to concerns over fuel security, price stability, and the sustainability of fuel sources. Concurrent reductions in particulate emissions from these alternative fuels are expected because of changes in fuel composition including reduced sulfur and aromatic content. The NASA AAFEX was conducted in January-February 2009 to investigate the effects of synthetic fuels on gas-phase and particulate emissions. Standard petroleum JP-8 fuel, pure synthetic fuels produced from natural gas and coal feedstocks using the Fischer–Tropsch (FT) process, and 50% blends of both fuels were tested in the CFM-56 engines on a DC- 8 aircraft. To examine plume chemistry and particle evolution with time, samples were drawn from inlet probes positioned 1, 30, and 145 m downstream of the aircraft engines. No significant alteration to engine performance was measured when burning the alternative fuels. However, leaks in the aircraft fuel system were detected when operated with the pure FT fuels as a result of the absence of aromatic compounds in the fuel. Dramatic reductions in soot emissions were measured for both the pure FT fuels (reductions in mass of 86% averaged over all powers) and blended fuels (66%) relative to the JP-8 baseline with the largest reductions at idle conditions. At 7% power, this corresponds to a reduction from 7.6 mg kg-1 for JP-8 to 1.2 mg kg-1 for the natural gas FT fuel. At full power, soot emissions were reduced from 103 to 24 mg kg-1 (JP-8 and natural gas FT, respectively). The alternative fuels also produced smaller soot (e.g., at 85% power, volume mean diameters were reduced from 78 nm for JP- 8 to 51 nm for the natural gas FT fuel), which may reduce their ability to act as cloud condensation nuclei. The reductions in particulate emissions are expected for all alternative fuels with similar reductions in fuel sulfur and aromatic content regardless of the feedstock. As the plume cools downwind of the engine, nucleation-mode aerosols form. For the pure FT fuels, reductions (94% averaged over all powers) in downwind particle number emissions were similar to those measured at the exhaust plane (84%). However, the blended fuels had less of a reduction (reductions of 30-44%) than initially measured (64%). The likely explanation is that the reduced soot emissions in the blended fuel exhaust plume results in promotion of new particle formation microphysics, rather than coating on pre-existing soot particles, which is dominant in the JP-8 exhaust plume. Downwind particle volume emissions were reduced for both the pure (79 and 86% reductions) and blended FT fuels (36 and 46%) due to the large reductions in soot emissions. In addition, the alternative fuels had reduced particulate sulfate production (near zero for FT fuels) due to decreased fuel sulfur content. To study the formation of volatile aerosols (defined as any aerosol formed as the plume ages) in more detail, tests were performed at varying ambient temperatures (-4 to 20 C). At idle, particle number and volume emissions were reduced linearly with increasing ambient temperature, with best fit slopes corresponding to- 8 × 1014 particles (kg fuel)-1 C-1 for particle number emissions and- 10 mm3 (kg fuel)-1 C-1 for particle volume emissions. The temperature dependency of aerosol formation can have large effects Authors Beyersdorf, A. J., Timko, M. T., Ziemba, L. D., Bulzan, D., Corporan, E., Herndon, S. C., Howard, R., Miake- Lye, R., Thornhill, K. L., Winstead, E., Wey, C., Yu, Z., and Anderson, B. E Source Atmos. Chem. Phys., Vol. 14, pp. 11- 23. Publication Date 2014

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 71 Reductions in Aircraft Particulate Emissions due to the use of Fischer–Tropsch Fuels on local air quality surrounding airports in cold regions. Aircraft- produced aerosols in these regions will be much larger than levels expected based solely on measurements made directly at the engine exit plane. The majority (90% at idle) of the volatile aerosol mass formed as nucleation-mode aerosols, with a smaller fraction as a soot coating. Conversion efficiencies of up to 2.8% were measured for the partitioning of gas-phase precursors (unburned hydrocarbons and SO2) to form volatile aerosols. Highest conversion efficiencies were measured at 45% power.

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 72 Reference 7 An Experimental Comparison of the Emissions Characteristics of Standard Jet A-1 and Synthetic Fuels Abstract Emissions characteristics of lean, turbulent, partially premixed swirled flames of synthetic fuels along with a standard Jet A-1 fuel are studied. The investigated synthetic fuels are (a) Fully synthetic jet fuel (FSJF), (b) Fischer–Tropsch synthetic paraffinic kerosene (FT-SPK), (c) FT-SPK+20 % hexanol, and (d) FT-SPK+50 % naphthenic cut. The measurements are performed in a tubular combustor equipped with a burner based on the principle of air-blast atomization. The exhaust gas compositions are measured using a non-dispersive infrared gas analyzer for carbon dioxide (CO2) and carbon monoxide (CO), a flame ionization detector for unburned hydrocarbons (UHC), and a chemical luminescence detector for nitric oxides (NO and NO2). The EI of CO and NOX of the investigated fuels are calculated using guidelines provided by the Society of Automotive Engineers (SAE). Measurements are performed at several combustor pressure levels, i.e., 0.3, 0.54 and 0.8 MPa, to compare the emissions behavior of the investigated fuels at varied operating conditions. At 0.3 MPa of combustor pressure, the order of fuels with their increasing formation of NOX are FSJF, FT-SPK+20 % hexanol, Jet A-1, FT-SPK+50 % naphthenic cut and neat FT-SPK. Differences in the observed NOX formation behavior of the investigated fuels are attributed to their probable different degrees of mixing with air in the combustor. At 0.8 MPa, no significant differences in their emissions characteristics are observed due to very low absolute values; hence we report that at higher pressure conditions which prevail in the aero-engine combustion systems, the emissions characteristics of tested synthetic fuels are very close to that of standard Jet A-1 fuel. Authors Bhagwan, R., Habisreuther, P., Zarzalis, N., and Turrini, F. Source Flow Turbulence Combustion, Vol. 92, pp.865–884. Publication Date 2014

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 73 Reference 8 Recent developments in studies of alternative jet fuel combustion: Progress, challenges, and opportunities Abstract With the growing air transport demand and concerns about its environmental impacts, alternative jet fuels derived from non- conventional sources have become an important strategy for achieving a sustainable and green aviation. In the past 10 years, governments around the world along with aviation industry have invested significant efforts into exploring all sorts of alternative jet fuels that can be used to power aircraft engines. Among all the alternative jet fuels explored, the aviation sector has agreed that hydrocarbon- based 'drop-in' replacement fuels, which are fully interchangeable and compatible with current conventional jet fuels, would be the best choice in the near future, as they can be used without any modifications to today's aircraft or fuel infrastructure. This paper reviews the current state of development of 'drop-in' alternative jet fuels including various FT synthetic jet fuels and bio-jet fuels. Recent advances in research activities on alternative jet fuels, including fuel property evaluations, combustor component tests, engine tests, and flight tests, are highlighted. Furthermore, basic research needs for understanding the combustion characteristics of alternative jet fuels are underlined and discussed by reviewing recent fundamental combustion studies on ignition, extinction, flame propagation, emissions. and species evolution of various conventional and alternative jet fuels. Recognizing that the use of 'simpler' surrogate fuels to emulate the behavior of 'complex' alternative jet fuels is of fundamental and practical importance for the development of physics- based models to enable quantitative emissions and performance predictions using combustion modeling, recent studies on surrogate formulation for alternative jet fuels are also reviewed and discussed. This review concludes with a brief discussion of future research directions. Authors Zhang, C., Hui, X., L. Yuzhen., and Sung, C. Source Renewable and Sustainable Energy Reviews Publication Date 2016

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 74 Reference 9 Aviation Gas Turbine Alternative Fuels: A Review Abstract During the last years, the aviation sector has been looking into alternatives to kerosene from crude oil, to combat climate change by reduction of greenhouse gas (GHG) emissions and to ensure security of supply at affordable prices. The efforts are also a reaction to commitments and policy packages. Currently, a wide range of possible fuel candidates and fuel blends are discussed in the triple feedstock, process, and product. Any (synthetic) aviation fuel must be certified; hence, a profound knowledge on its properties, in particular thermophysical and chemical, is inevitable. In the present paper, an overview is given on alternative jet fuels, looking into the short-term and long-term perspective. Examples focusing on experimental and modeling work of combustion properties of existing—coal to liquid, gas to liquid (GtL)—and possible alternative fuels—GtL + 20 % 1-hexanol, GtL + 50 % naphthenic cut—are presented. Ignition delay times and laminar flame speeds were measured for different alternative aviation fuels over a range of temperatures, pressures, and fuel–air ratios. The data are used for the validation of a detailed chemical reaction mechanism following the concept of a surrogate. Such validated reaction models able to describe and to predict reliably important combustion properties of jet fuels are needed to further promote the development of even more sophisticated jet engines and to optimize synthetic jet fuel mixtures in practical combustors. Authors Blakey, S., Rye, L., Wilson, C.W. Source Proceedings of the Combustion Institute, Vol. 33, November 9, pp.2863-2885. Publication Date 2010

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 75 Reference 10 Evaluation of Bio-Derived Synthetic Paraffinic Kerosenes (Bio-SPK) Abstract It is of paramount importance that our industry must continue to progressively improve its environmental performance and lessen impacts to the global ecosystem, while continuing to reduce operating costs. Aviation recognizes these challenges must be addressed to ensure industry viability and is actively seeking to provide technologically driven solutions. Bio-derived jet fuel is a key element in the industry strategy to address these challenges. The signatories to this summary and many others have invested significant time and resources to further the research, development and commercialization of bio-derived jet fuel. Virgin Atlantic paved the way with its proof of concept flight powered by biofuel in February 2008. Since that time, a broader range of fuels have become available that more closely replicate the performance characteristics of conventional kerosene jet fuel. Significant progress has been made in verifying the performance of SPK made from sustainable sources of bio-derived oils, that can be used in commercial aircraft at a blend ratio of up to 50 percent with traditional jet fuel (Jet A or Jet A-1). A cross-industry team consisting of Boeing, Honeywell/UOP, Air New Zealand, Continental Airlines (CAL), Japan Airlines (JAL), General Electric, CFM, Pratt & Whitney, and Rolls Royce participated in a series of tests flights with a bio- derived SPK (Bio-SPK) to collect data to support eventual certification of Bio-SPK jet fuels for use in commercial aviation pending the necessary approvals. This document provides a summary of the data collected from the Bio-SPK research and technology program, as well as a discussion about the additional data that is being generated to support fuel approval. Authors Boeing Company Source UOP, U.S. Air Force Research Laboratory, Report Version 5.0, Committee D02 on Petroleum Products and Lubricants, Subcommittee D02.J0.06 on Emerging Turbine Fuels, Research Report D02- 1739. ASTM International, West Conshohocken, PA Publication Date June 28, 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 76 Reference 11 Effects of Fuel Aromatic Content on Nonvolatile Particulate Emissions of an In-Production Aircraft Gas Turbine Abstract Aircraft engines emit particulate matter (PM) that affects the air quality in the vicinity of airports and contributes to climate change. Nonvolatile PM (nvPM) emissions from aircraft turbine engines depend on fuel aromatic content, which varies globally by several percent. It is uncertain how this variability will affect future nvPM emission regulations and emission inventories. Here we present BC mass and nvPM number EIs as a function of fuel aromatic content and thrust for an in-production aircraft gas turbine engine. The aromatics content was varied from 17.8 % (v/v) in the neat fuel (Jet A-1) to up to 23.6 % (v/v) by injecting two aromatic solvents into the engine fuel supply line. Fuel normalized BC mass and nvPM number EIs increased by up to 60% with increasing fuel aromatics content and decreasing engine thrust. The EIs also increased when fuel naphthalenes were changed from 0.78 % (v/v) to 1.18 % (v/v) while keeping the total aromatics constant. The EIs correlated best with fuel hydrogen mass content, leading to a simple model that could be used for correcting fuel effects in emission inventories and in future aircraft engine nvPM emission standards. Authors Brem, T.B., et al Source Environmental Science & Technology, Vol. 49, Issue 22, pp.13149-13157 Publication Date October 23, 2015

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 77 Reference 12 Characterization of Gaseous and Particulate Emissions from a Turboshaft Engine Burning Conventional, Alternative, and Surrogate Fuels Abstract The effect of fuel composition on the operability and gaseous and PM emissions of an Allison T63-A-700 turboshaft engine operated at four power settings was investigated in this effort. Testing was performed with a specification JP-8, a SPK, and four two-component surrogate mixtures that comprise compound classes within current and future alternative fuels. Comparable engine operability was observed for all fuels during this study. Major gaseous emissions were only slightly effected, with trends consistent with those expected based on the overall hydrogen content of the fuels. However, minor hydrocarbon and aldehyde emissions were significantly more sensitive to the fuel chemical composition. Linear correlations between speciated hydrocarbon and aldehyde emissions were observed over the full engine operating range for the fuels tested. The corresponding slopes were dependent on the fuel composition, indicating that fuel chemistry affects the selectivity to specific decomposition pathways. Unburned fuel components were observed in the engine exhaust during operation with all fuels, demonstrating that completely unreacted fuel compounds can pass through the high temperature/pressure combustion zone. Nonvolatile PM emissions (soot) were strongly affected by the fuel chemical composition. Paraffinic fuels produced significantly lower PM number and mass emissions relative to aromatic-containing fuels, with the paraffin structure affecting sooting propensity. The observations are consistent with those expected based on simplified soot formation mechanisms, where fuels with direct precursors for polycyclic aromatic hydrocarbon formation have higher PM formation rates. The effect of a specific chemical structure on the relative PM production is important as this would not be evident when comparing sooting tendencies of fuels based on bulk fuel properties. All fuels produced similar single log-normal size distributions of soot, with higher sooting fuels producing larger mean diameter particles. It is hypothesized that the controlling growth and formation mechanisms for PM production are similar for different fuel chemistries in this regime, with composition primarily affecting soot formation rate. This hypothesis was supported by preliminary TEM analyses that showed similar soot microstructures during operation with either conventional JP-8 or alternative fuels. Overall, this study provides additional and improved insight into the effect of fuel chemical composition on complex combustion chemistry and emissions propensity in a gas turbine engine and can assist with the successful development of predictive modeling tools. Authors Cain, J., DeWitt, M.J., Blunck, D., Corporan, E., Striebich, R., Anneken, D., Klingshirn, C., Roquemore, W.M., and Vander Wall, R. Source Energy Fuels, Vol. 27, pp.2290−2302 Publication Date 2013

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 78 Reference 13 Energy and Environmental Viability of Select Alternative Jet Fuel Pathways Abstract This paper analyzes alternative jet fuels in terms of how they could change emissions from military and civil aircraft and in terms of the challenges in meeting future energy goals. Estimations of the continental United States (CONUS) conventional jet fuel energy usage for the civil and military aviation fleets were used to inform the magnitude and logistics of where the fuels would be needed. To adequately meet military goals, the U.S. Air Force (USAF) and U.S. Navy (USN) would need to supply roughly 47,500 bpd and 18,800 barrels per day (bpd) of alternative jet fuels by 2016, respectively. The total amount of fuel for both military and civil goals would reach nearly 132,000 bpd within the next decade if tentative goals become actual policy. Quantifications of the emissions affecting surface air quality from CONUS civil, USAF and USN aircraft, as well as 50% and 100% SPK combustion emissions normalized by conventional jet fuels were also provided. Although a 50% blend of SPK has been permitted, additional testing and analysis is needed for approval of higher blend percentages. It was found that NOX emissions from military aircraft tend be lower while primary PM2.5, CO and UHC emissions tend to be higher than their civilian aircraft counterparts. This is indicative of military aircraft being less efficient at lower power settings than civil aircraft during the LTO cycle. Emissions reductions with 50% and 100% SPK use could provide military and civil aviation planners with more options when locating aircraft in nonattainment areas within the CONUS. For some emissions, the introduction of SPK fuels could allow for additional aircraft for the same environmental impact or decreased overall air quality footprint for a particular location. SPK fuels from Fischer–Tropsch Biomass-to-Liquid (BTL) and HRJ processes were examined for their ability to meet future alternative fuel and environmental goals. BTL facilities were found to have larger capital costs and HRJ required large land area. Life-cycle analysis (LCA) of greenhouse gas (GHG) emissions for select F-T BTL and HRJ were found to potentially meet or exceed organizational goals in the near term. High yield crops like algae could provide the energy and environmental goals, but additional constraints must be considered, such as water and CO2 requirements; furthermore, these technologies need to be translated from the lab to commercial production. Additional research is required to provide an in-depth geographic analysis of the CONUS commercial and military demand centers and resource constraints to better understand the challenge in meeting future alternative fuel goals. Authors Carter, N. A., Stratton, R.W., Bredehoeft, M.K., and Hileman, J.I Source 47th AIAA/ASME, SAE, ASEE Joint Propulsion Conference & Exhibit. AIAA 2011-5968. San Diego, CA Publication Date July 31 – August 3, 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 79 Reference 14 Environmental and Economic Assessment of Microalgae-Derived Jet Fuel Abstract Significant efforts must be undertaken to quantitatively assess various alternative jet fuel pathways when working towards achieving environmental and economic United States commercial and military alternative aviation fuel goals within the next decade. This thesis provides LCAs of the environmental and economic impacts of cultivating and harvesting phototrophic microalgae; extracting, transporting, and processing algal oils to hydrocarbon fuels; and distributing and combusting the processed renewable jet fuel for a pilot scale facility. Specifically, life-cycle greenhouse gas (GHG) emissions, production costs, freshwater consumption, and land use were quantified for four cultivation and two extraction technology sets. For each cultivation and extraction type, low, baseline, and high scenarios were used to assess the variability of each performance metric. Furthermore, sensitivity analyses were used to gain insights as to where efforts towards improving certain technologies could have the largest impact on improving the life-cycle metrics. The four cultivation technologies include open raceway ponds, horizontal serpentine tubular photobioreactors (PBRs), vertical serpentine tubular PBRs, and vertical flat panel PBRs. Open raceway ponds were modeled from previous literature, while the PBRs were modeled, validated and optimized for specific constraints and growth inputs. The algal oil extraction techniques include conventional dewatering, drying, and extraction using hexane in a similar process to seed oil extraction (termed dry extraction in this study) as well as algal cell lysing with steam and potassium hydroxide as well as fluid separation and washing processes (termed wet extraction). Overall, open raceway pond cultivation with wet extraction performed most favorably when compared with the other scenarios for GHG emissions, production costs, freshwater consumption, and areal productivity (including the entire cultivation and extraction facility), yielding 31.3 g-CO2e/MJHEFA- J, 0.078 $/MJHEFA-J (9.86 $/galHEFA-J), 0.38 Lfreshwater/MJHEFA-J and 17,600 LTAG/ha/yr for the baseline cases with brackish water makeup. The life-cycle GHG emissions and production cost metrics for the open raceway pond with wet extraction low scenario were both lower than that of conventional jet fuel baselines. For all cases, the inputs most sensitive to the life-cycle metrics were the cultivation system biomass areal productivity, algal extractable lipid weight fraction, and downstream harvesting system choices. Authors Carter, N. A. Source Laboratory for Aviation and the Environment. Massachusetts Institute of Technology. Cambridge, MA Publication Date June 2012

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 80 Reference 15 Characterization of Emissions from the Use of Alternative Aviation Fuels, Journal of Engineering for Gas Turbines and Power Abstract 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) 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 PM 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. Authors Chan, T.W., Chishty, W. A., Canteenwalla, P., Buote, D., and Davidson, C.R. Source Journal of Engineering for Gas Turbines and Power, Vol. 138 / 011506-1 Publication Date January 2016

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 81 Reference 16 Experimental Study of the Gaseous and Particulate Matter Emissions from a Gas Turbine Combustor Burning Butyl Butyrate and Ethanol Blends Abstract This paper reports the gaseous pollutants and PM emissions of a gas turbine combustor burning butyl butyrate and ethanol blends. The gas turbine has been tested under two operational conditions to represent the cruising (condition 1) and idling (condition 2) conditions of aero engines. Aviation kerosene RP-3 and four different biofuels using butyl butyrate (BB) and ethanol blends were tested and compared to evaluate the impact of fuel composition on CO, NOx, unburnt hydrocarbon (UHC) and PM emissions under selected two operational conditions. The PM number (PN) concentration and size distributions were measured by a SMPS. The compositions of filter borne PM were analysed by ion chromatograph technique. The concentrations of CO, NOx and UHC were detected and analysed by a gas analyser. Results indicated that under idling and cruising conditions the CO emissions from BB and ethanol blends were higher than that of RP-3 due to the relatively lower combustion temperature of the biofuels compared with that of RP-3. Results of the NOx emission comparison indicated the biofuels produced less NOx than RP-3 and the increase of ethanol content in the biofuels could reduce the NOx and UHC emissions. The particles smaller than 20 nm played a dominant role in PN emissions at condition 1 with the range from 2 × 106/cm3 to 4 × 107/cm3. There was a peak value of particle number concentration with the particle size ranging from about 25 nm and 40 nm. The PN emission index at condition 1 was higher than that at condition 2 for the biofuels, while the trend was opposite to that of RP-3. The ions analysis indicated Ca2+ and SO42− were the two dominant ions in the PM emissions of biofuels. Authors Chen, L. Zhang, Z. Lu, Y., Zhang, C., Zhang, X., Zhang, Cu., Roskilly, A.P. Source Applied Energy, Vol.195, pp.693-701 Publication Date 2017

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 82 Reference 17 D4.3 Emissions Report and Database of Systems Key Performance Parameters Abstract In the development of alternative fuels for aviation there have been a number of significant scale research projects within the EU: SWAFEA (2008-2011) investigated the impact and feasibility of using alternative fuels in aviation; Alfabird (2009-2012) evaluated a selection of ‘best candidate’ alternative fuels; and most recently Initiative Towards sustAinable Kerosene for Aviation (ITAKA) (2012-2015) an intermediate scale ‘value chain’ project that aims to produce, flight-test and evaluate 4000 tonnes of sustainable biofuels. The ITAKA project is a collaborative research venture designed to address some of the barriers that challenge the development of sustainable aviation biofuels in the EU. In the following task, the direct emissions from the combustion of the ITAKA MCA batch biofuel in a small gas turbine engine are assessed so that their environmental impact can be placed in context and better understood. This is an important issue since aviation emissions can have a direct impact on atmospheric chemistry and on the radiative balance that extends well beyond the CO2 effect: Contrails formed by condensation of water vapour onto exhaust PM and aerosols may trigger the formation of induced cirrus clouds, similarly, emissions of NOx may perturb the natural chemical cycles and lead to ozone production or destruction depending on latitude and altitude as well as modifying the time of residence for methane in the atmosphere. Hence, modeling the atmospheric impact of aviation requires the synthesis of aircraft movement data and detailed aircraft emissions data into atmospheric models. And while the combustion of fuel in a gas turbine engine is a highly efficient process, there is no reason to assume that the emissions from HEFA based fuels will be identical to those from the combustion of Jet A-1. Due diligence requires that the emission profile for the combustion of these fuels must come under scientific scrutiny ahead of the large scale introduction of new fuels on climate, security or economic grounds. The ITAKA HEFA based biofuels are produced with properties that are within the specification envelope of ASTM D7566, however there are appreciable chemical and physical differences. The impact of these differences on aircraft emissions is largely unknown, although some consensus and generalized rules are beginning to emerge. The objective of this task has been to collect experimental emission data using a small APU gas turbine engine and consolidate this with structured knowledge from the wider literature. In comparison to full rig testing or on-wing testing, emission testing on an APU has the advantage that a comparatively modest quantity of fuel is required, tests are relatively low cost, and the information gained is comparable since fuel chemistry is the dominant impact parameter. The experimental data capture the important emission characteristics and key features of engine performance when powered by ITAKA MCA HEFA based biofuel. A full range of fuel blend ratios has been considered from 100% Jet A-1 through to 100% biofuel. This is the largest most comprehensive dataset in the literature. It has been extended to cover the range of blends beyond the current ASTM 50% certification limit which may be important in future certification, and Authors Christie, S. Source ITAKA Collaborative Project, FP7- 308807 Publication Date April 30, 2015

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 83 D4.3 Emissions Report and Database of Systems Key Performance Parameters allows performance and emission trends to be assessed with statistically significant confidence. The ITAKA MCA biofuel sourced from SkyNRG was derived from used cooking oil, while a straight run Jet A-1 sourced from within the UK was used as both baseline and blend component fuel. A complete GC x GC analysis of the MCA biofuel and baseline Jet A-1 provided a comprehensive qualitative and quantitative chemical breakdown of the fuel groupings, and showed that the aromatic, alkane and cyclo-paraffinic structures in the two fuels are significantly different.

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 84 Reference 18 Gas Turbine Engine Nonvolatile Particulate Matter Mass Emissions: Correlation with Smoke Number for Conventional and Alternative Fuel Blends Abstract This study evaluates the relationship between the emissions parameters of smoke number (SN) and mass concentration of nonvolatile PM (nvPM) in the exhaust of a gas turbine engine for a conventional Jet A-1 and a number of alternative fuel blends. The data demonstrate the significant impact of fuel composition on the emissions and highlight the magnitude of the fuel-induced uncertainty for both SN within the Emissions Data Bank as well as nvPM mass within the new regulatory standard under development. Notwithstanding these substantial differences, the data show that correlation between SN and nvPM mass concentration still adheres to the First Order Approximation (FOA3), and this agreement is maintained over a wide range of fuel compositions. Hence, the data support the supposition that the FOA3 is applicable to engines burning both conventional and alternative fuel blends without adaptation or modification. The chemical composition of the fuel is shown to impact mass and number concentration as well as geometric mean diameter of the emitted nvPM; however, the data do not support assertions that the emissions of BC with small mean diameter will result in significant deviations from FOA3. Authors Christie, S., Lobo, P., Lee, D., Raper, D. Source Science & Technology, Vol. 51, 2017, pp.988-996. Publication Date 2017

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 85 Reference 19 An Overview of the National Jet Fuels Combustion Program Abstract This paper provides an overview of the National Jet Fuels Combustion Program led by the Federal Aviation Administration, the U.S. Air Force Research Laboratory, and the NASA. The program follows from basic research from the U.S. Air Force Office of Scientific Research and results from the engine-company-led Combustion Rules and Tools program funded by the U.S. Air Force. The overall objective of this fuels program was to develop combustion-related generic test and modeling capabilities that can improve the understanding of the impact of fuel chemical composition and physical properties on combustion, leading to accelerating the approval process of new alternative jet fuels. In this paper, the motivation and objectives for the work, participating universities, gas turbine engine companies, other federal agencies, and international partners are described. Authors Colket, M., Heyne, J., Rumizen, M., Gupta, M., Jardines, A., Edwards, T., Roquemore, W. M., Andac, G., Boehm, R., Zelina, J., Lovett, J., Condevaux, J., Bornstein, S., Rizk, N., Turner, D., Graves, C., Anand, M.S. Source AIAA SciTech Forum 54th AIAA Aerospace Sciences Meeting, San Diego, CA Publication Date January 4-8, 2016

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 86 Reference 20 Alternative Fuels Tests on a C-17 Aircraft: Emissions Characteristics Abstract Emissions evaluations were conducted on a C-17 Globemaster III F117-PW-100 engine operated with alternative fuels blends. These tests support the USAF goal of 50% domestic fuel consumption using alternative (synthetic) fuels with lower or equal carbon footprint than petroleum fuels by 2016. The tests took place at Edwards Air Force Base on the period of August 16 through 27, 2010 as part of the United States Air Force (USAF) Alternative Fuels Certification Office ground and flight tests to certify the C-17 on a 50/50 by volume JP- 8/HRJ fuel blend. Emissions were collected from engine 3 of the parked aircraft operated on conventional JP-8 and 50/50 blends of JP- 8 and a beef tallow-derived HRJ, and a 50/25/25 blend of JP-8, HRJ and a coal-derived Fischer–Tropsch (FT) fuel. Gaseous and PM emissions were measured. PM measurements included particle number (concentration), mass and size distribution. In addition, HAPs emissions, SNs and chemical analysis of soot samples were performed for the engine operated with the three fuels. Emissions were collected for five engine operating conditions ranging from 4% (idle) to 63% of rated maximum thrust. Test results show that the alternative fuel blends resulted in no operational anomalies or detrimental impacts on the gaseous or PM emissions of the F117 engine for any of the conditions tested. Moderate reductions in carbon monoxide (CO) emissions (30%) and more significant reductions in sulfur oxides (50%), measured HAPs (60%) and PM emissions (30- 60%) relative to operation with JP-8 were observed. The alternative fuels had negligible impact on nitrogen oxides (NOx) emissions. Authors Corporan, E., DeWitt, M.J., Klingshirn, C.D., Anneken, D. Source Air Force Research Laboratory Interim Report, AFRL-RZ-WP-TR-2011- 2004, Wright-Patterson Air Force Base, OH, December 2010 Publication Date December 2010

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 87 Reference 21 Chemical, Thermal Stability, Seal Swell, and Emissions Studies of Alternative Jet Fuels Abstract This effort describes laboratory evaluations of six alternative (non- petroleum) jet fuel candidates derived from coal, natural gas, Camelina, and animal fat. Three of the fuels were produced via Fischer−Tropsch (FT) synthesis, while the other three were produced via extensive hydroprocessing. The thermal stability, elastomer swell capability, and combustion emissions of the alternative jet fuels were assessed. In addition, detailed chemical analysis was performed to provide insight into their performance and to infer potential behavior of these fuels if implemented. The fuels were supplied by Sasol, Shell, Rentech, UOP, and Syntroleum Corporation. Chemical analyses show that the alternative fuels were comprised of mostly paraffinic compounds at varying relative concentrations, contained negligible heteroatom species, and were mostly aromatic-free. The six paraffinic fuels demonstrated superior thermal oxidative stability compared to JP-8, and therefore, have increased resistance to carbon formation when heated and can be exposed to higher temperatures when used to cool aircraft systems. Material compatibility tests show that the alternative fuels possess significant seal swelling capability in conditioned nitrile O-rings; however, elastomer swelling was significantly lower than for JP-8, which may likely result in fuel leaks in aircraft systems. Engine tests with the alternative fuels demonstrated no anomalies in engine operation, production of significantly lower nonvolatile PM (soot), and moderately lower unburned hydrocarbons and carbon monoxide emissions compared to baseline JP-8 fuel. Also, no penalty (i.e., increase) in fuel flow requirement for equal engine power output was observed. In general, this study demonstrates that paraffinic fuels derived from different feedstocks and produced via FT synthesis or hydroprocessing can provide fuels with very similar properties to conventional fuels consisting of excellent physical, chemical, and combustion characteristics for use in turbine engines. These types of fuels may be considered as viable drop-in replacement jet fuels if deficiencies such as seal swell, lubricity, and low density can be properly addressed. Authors Corporan, E., Edwards, T., Shafer, L., DeWitt, M.J., Klingshirn, C.D., Zabarnick, S., West, Z., Striebich, R., Graham, J., Klein, J. Source Energy & Fuels, Vol. 25, pp.955-966 Publication Date March 2, 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 88 Reference 22 Comparison of Emissions Characteristics of Several Turbine Engines Burning Fischer-Tropsch and Hydroprocessed Esters and Fatty Acids Alternative Jet Fuels Abstract A summary of the impacts of alternative fuel blends on the gaseous and PM (mostly soot) emissions of aircraft turbine engines is presented. Six engines were studied under several U.S. Air Force and NASA sponsored programs to assess the impacts of the alternative (non-petroleum) fuels on emissions and/or to support the certification of military aircraft for the use of 50/50 (by volume) alternative fuel/JP-8 blends. One turboshaft (T63) and five turbofan (CFM56-7, CFM56-2, F117, TF33 and PW308) engines were studied. Fuels derived from coal and natural gas produced via Fischer–Tropsch (FT) synthesis, and fuels from animal fats and plant oils produced via hydroprocessing [hydroprocessed esters and fatty acids] were evaluated. Trends of alternative fuel impacts on emissions compared to conventional fuel for the different engine types are discussed. Results consistently show significant reductions in PM emissions with the alternative fuel blends compared to operation with conventional fuels. These relative reductions were observed to be lower as engine power increased. Engines operated with different alternative fuel blends were found to produce similar slopes of normalized particle number to engine power with only the magnitude of the reductions being a function of the fuel type. These results suggest that it may be plausible to predict particle number emissions from turbine engines operated on alternative fuels based on engine, engine setting, limited PM data and fuel composition. Gaseous emissions measurements show modest reductions of carbon monoxide, unburned hydrocarbons and HAPs with the alternative fuels for several engines; however, no clear dependency of fuel impacts based on engine characteristics were observed. Authors Corporan, E., DeWitt, M.J., Klingshirn, C.D., Anneken, D., Shafer, L., Striebich, R. Source Proceedings of ASME Turbo Expo 2012, Copenhagen, Denmark Publication Date June 11-15, 2012

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 89 Reference 23 Reduced Emissions Via Synthesized Aromatic Kerosene Abstract Virent provides a low cost, bio-based route to drop-in products. Its BioForming® Technology is a leading catalytic route that allows feedstocks to direct replacement fuels and chemicals. Virent’s technologies provide many competitive advantages, such as a continuous, catalytic process with higher yields of aromatic chemicals and fuels, competitive economics at commercial scale, and feedstock flexibility. As one component of a partnership between Virent and Shell focused on technology and product qualification, this study sought to demonstrate the potential of synthetic aromatic kerosenes (SAKs) in the Alternative Jet Portfolio to provide benefits over conventional jet fuel aromatics. Gaseous and particulate emissions from a turbojet engine burning SAK blends and Jet A blends with equal aromatic levels at different power settings were measured in a simulated altitude chamber. Results showed 35% - 70% reductions in nvPM number and mass due to SAK blends over a range of power and altitude conditions. There was no detectable difference in combustor performance on SAK blends vs. Jet A blends. Authors Daily, B., Ginestra, C Source Virent briefing to ASCENT Seattle, WA Publication Date October 13, 2015 No link is publicly available for this document. Access must be requested. Contact Link: https://ascent.aero/contact/

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 90 Reference 24 Alternative Aviation Fuel Experiment II (AAFEX II) Overview Abstract Description and results from the Alternative Aviation Fuel Experiment II (AAFEX II). The objective of this experiment was to perform static aircraft engine testing using Hydrotreated Renewable Jet (HRJ) and other fuels to determine effects on engine performance and emissions. Also, examine methodologies for particle sampling to assist the SAE – E-31 Aircraft Particle Measurement Subcommittee in developing a standard particle sampling technique. Authors Del Rosario, R., Koudelka, J., Wahls, R., Madavan, N., Bulzan, D. Source NASA Presentation, Interagency Working Group – Alternative Fuels Publication Date September 19, 2012

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 91 Reference 25 Scaling Air Quality Effects from Alternative Jet Fuel in Aircraft and Ground Support Equipment Abstract Many of the nation's largest airports, including Los Angeles International Airport, the Hartsfield-Jackson Atlanta International Airport, Chicago O'Hare International Airport and Washington Dulles International Airport are located within areas designated by the EPA as having ambient PM concentrations that exceed National Ambient Air Quality Standards. When inhaled, fine PM can enter the blood stream from the lungs and increase the risk of illness and premature mortality. This thesis examines the potential of two jet fuel types, ultra low-sulfur jet fuel and SPK, to reduce aviation's contribution to ambient PM concentrations. Scaling factors were developed for airport criteria pollutant emissions to model alternative jet fuels in aircraft and ground support equipment. These linear scaling factors were based on currently published studies comparing standard diesel and jet fuels with alternative jet fuels. It was found that alternative jet fuels lower or maintain all air pollutant emissions considered (primary PM, sulfur oxides, nitrous oxides, unburned hydrocarbons and carbon monoxide) for both aircraft and ground support equipment. To quantify the potential benefits of changing fuel composition on ambient PM concentrations, a study of the Atlanta Hartsfield-Jackson International Airport was completed using both emissions inventory analysis and atmospheric modeling. The atmospheric modeling captures both primary PM and other emissions that react in the atmosphere to form secondary PM. It was found that the use of an ultra low-sulfur jet fuel in aircraft gas turbines could reduce the primary PM inventory by 37% and SPK could reduce the primary PM inventory by 64%. The atmospheric modeling predicts that an ultra low-sulfur jet fuel in aircraft could reduce ambient PM concentrations due to aircraft by up to 57% and SPK could reduce PM concentrations due to aircraft by up to 67%. Thus, this study indicates that the majority of air quality benefits at Atlanta Hartsfield-Jackson International Airport that could be derived from the two fuels considered can be captured by removing the sulfur from jet fuel through the use of an ultra low-sulfur jet fuel. Authors Donohoo, P. Source M.Sc. Thesis, Massachusetts Institute of Technology, Cambridge, MA Publication Date 2010

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 92 Reference 26 Evaluation of Alcohol to Jet Synthetic Paraffinic Kerosenes (ATK-SPK) Abstract In 2009 a new ASTM specification (D7566-09, Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons) was developed for aviation turbine fuels. Contained in D7566-09 is a specification for a SPK blend component made from synthesis gas using the Fischer–Tropsch process commonly referred to as FT-SPK. Also contained in D7566-09 is a specification for a blend of FT-SPK with conventional petroleum-based jet fuel. The specification allows for a maximum of a 50% blend of FT-SPK with conventional jet fuel. A new annex, A2, was added which presents a specification for the hydroprocessed esters and fatty acids SPK made from Bio-Oils. Annex A2 specification also allows for a maximum of a 50% (v) blend of HEFA-SPK with conventional jet fuel. It’s the intent of this report to demonstrate that a suitable SPK can be produced from an alcohol source (ATJ-SPK) that can satisfy the requirements outlined in D7566- 12A and be considered for Annex A4. Further, it’s also the intent of this report to demonstrate that a 50% (v) ATJ-SPK fuel blend with conventional petroleum jet fuel is suitable for use in turbine engines for commercial aviation. The report followed the guidelines outlined in the current version of ASTM D4054, “Standard Practice for the qualification and approval of new Aviation Turbine Fuels and Fuels Additives”. Samples of ATJ-SPK fuels were provided from 5 different fuel producers (Gevo Inc., LanzaTech, Swedish Biofuels, Cobalt/Navy, and UOP) using a variety of alcohol feedstocks. The 100% and 50% (v) ATJ-SPK fuels were compared to 100% and 50% (v) FT-SPK and HEFA-SPK fuels using the same analytical method and plotted on the same graph whenever possible. FT-SPK fuel samples were produced by Sasol, Syntroleum, Shell and with HEFA-SPK fuels produced by UOP. This report contains an extensive amount of analytical fit-for- purpose testing that was performed on the ATJ-SPK, HEFA-SPK, and FT-SPK neat and 50% fuel blends and this report includes engine ground test data specific for the ATJ-SPK fuel blends conducted by GE/CFM, Rolls Royce, Pratt & Whitney, and Honeywell. The engine ground tests included performance, operability, and emission testing. Authors Edwards, T., Meyer, D., Johnston, G., McCall, M., Rumizen, M., Wright, M. Source Report Version (1.10), Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, Subcommittee D02.J0 on Aviation Fuels, Research Report D02-1828, ASTM International, West Conshohocken, PA Publication Date April 1, 2016 No link is publicly available for this document. Access must be requested. Contact Link: https://www.astm.org/CONTACT/

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 93 Reference 27 Particulate Emissions Hazards Associated with Fueling Heat Engines Abstract All hydrocarbon- (HC-) fueled heat engine exhaust (tailpipe) emissions (<10 to 140 nm) contribute as health hazards, including emissions from transportation vehicles (e.g., aircraft) and other HC-fueled power systems. CO2 emissions are tracked and, when mapped, show outlines of major transportation routes and cities. Particulate pollution affects living tissue and is found to be detrimental to cardiovascular and respiratory systems where ultrafine particulates directly translocate to promote vascular system diseases potentially detectable as organic vapors. This paper discusses aviation emissions, fueling, and certification issues, including heat engine emissions hazards, detection at low levels and tracking of emissions, and alternate energy sources for general aviation. Authors Hendricks, R.C., Bushnell, D Source International Journal of Rotating Machinery, Article ID 415296 Publication Date March 18, 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 94 Reference 28 Comparison of Combustion Properties Between a Synthetic Jet Fuel and Conventional Jet A-1 Abstract Aviation fuel is a petroleum product that fulfills the Standard Specification for Aviation Turbine Fuels. Crude oil has been the raw material for production of aviation fuels for many years. Since the availability of crude oil is predicted to be limited in the future, alternative raw materials for aviation fuels are highly desirable. A Swedish company, Oroboros AB, has developed a novel clean synthetic jet fuel, LeanJet®. The fuel is produced synthetically from synthesis gas (Syngas) by the Fischer–Tropsch process. A comparative experimental investigation of combustion properties has been performed, comparing the synthetic jet fuel with Jet A1. The following parameters were investigated in an atmospheric combustor, which was originally designed for a Volvo Aero turbine (VT40): • Emissions of NOx, CO and HC; • Ignition and extinction points; • Liner temperatures; • Soot levels in the combustor. The emission measurements showed good combustion efficiency with low HC and CO for both fuels. With very lean mixtures, however, both the CO and the HC levels increased for the synthetic fuel. The nitrous oxides for the synthetic jet fuel were reduced over the operation conditions investigated. Qualitative reduction of soot levels was also seen for the synthetic jet fuel. The fuels showed no difference in material temperature along the combustor wall. Small differences in ignition characteristics were found, but no differences in extinction were observed. Authors Hermann, F. Source Proceedings of ASME Turbo Expo, GT2005-68540, Nevada Publication Date 2005

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 95 Reference 29 Effect of Soot Structure Evolution from Commercial Jet Engine Burning Petroleum Based JP-8 and Synthetic HRJ and FT Fuels Abstract Soot from jet engines is relevant to environmental and health concerns. In this study, JP-8, HRJ (hydrotreated renewable jet), and FT fuels were tested in a CFM56-2C1 engine on a DC-9 aircraft. Comparisons of PM physical structure at length scales spanning aggregate to primary particle to nanostructure, all by TEM, are reported. Petroleum-based JP-8 derived soot shows the nanostructure progression from amorphous to graphitic-like as a function of increasing engine power. Soots from the renewable HRJ and FT fuels exhibit significant nanostructure at each power level. Results are interpreted in terms of different soot formation regions with associated variations in temperature and local equivalence ratio. The driver for such differences is the nascent fuel composition, more specifically the different classes of components therein. Authors Huang, C.J., Vander Wal, R.L. Source Energy and Fuels, Vol. 27, pp.4946- 4958. Publication Date July 24, 2013

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 96 Reference 30 ICAO Airport Air Quality Manual Abstract This manual covers an evolving area of knowledge and represents currently available information that is sufficiently well-established to warrant inclusion in international guidance. This manual covers issues related to the assessment of airport-related air quality that are either specifically within the remit of the ICAO (such as main engine emissions) or where there is an established understanding of other non-aircraft sources (such as boilers, ground support equipment and road traffic) that will contribute, to a greater or lesser extent, to the impact on air quality. There are potential emissions source issues relevant to but not covered in this manual (e.g. forward speed effects of aircraft, influence of ambient conditions on aircraft emissions, aircraft start-up emissions, aircraft brake and tire wear) that have been identified and are the subject of further investigation by ICAO, Member States, observer organizations or other expert organizations, taking into account practical experience. This first edition of the manual includes chapters on the regulatory framework and drivers for local air quality measures; emissions inventory practices and emissions temporal and spatial distribution; completed emissions inventory (including a detailed sophisticated aircraft emissions calculation approach); dispersion modeling; airport measurements; mitigation options; and interrelationships associated with methods for mitigating environmental impacts. Throughout the document, additional references are provided for those interested in exploring these topics in further detail. This is intended to be a living document, and as more knowledge on this subject becomes available, it will be updated accordingly. Authors International Civil Aviation Organization (ICAO) Source (1st ed.). Montreal, Quebec, CA Publication Date 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 97 Reference 31 Health Effects of Ambient Air Pollution, How Safe is the Air We Breathe? Abstract Health Effects of Ambient Air Pollution aims to provide the reader with an overview of the health effects of air pollution in human subjects. The majority of the book is devoted to the discussion of the health effects of common wide-spread air pollutants regulated by the U.S. Environmental Protection Agency through National Ambient Air Quality Standards. The book reviews the sources and fate of common air pollutants in ambient air and researches the adverse effects of these outdoor and indoor air pollutants in 'in vivo' cell systems, animals, and humans. Authors Koenig, J.Q. Source Kluwer Academic Publication Date 2000

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 98 Reference 32 Hazardous Air Pollutants and Asthma Abstract Asthma has a high prevalence in the United States, and persons with asthma may be at added risk from the adverse effects of HAPs. Complex mixtures (fine PM and tobacco smoke) have been associated with respiratory symptoms and hospital admissions for asthma. The toxic ingredients of these mixtures are HAPs, but whether ambient HAP exposures can induce asthma remains unclear. Certain HAPs are occupational asthmagens, whereas others may act as adjuncts during sensitization. HAPs may exacerbate asthma because, once sensitized, individuals can respond to remarkably low concentrations, and irritants lower the bronchoconstrictive threshold to respiratory antigens. Adverse responses after ambient exposures to complex mixtures often occur at concentrations below those producing effects in controlled human exposures to a single compound. In addition, certain HAPs that have been associated with asthma in occupational settings may interact with criteria pollutants in ambient air to exacerbate asthma. Based on these observations and past experience with 188 HAPs, a list of 19 compounds that could have the highest impact on the induction or exacerbation of asthma was developed. Nine additional compounds were identified that might exacerbate asthma based on their irritancy, respirability, or ability to react with biological macromolecules. Although the ambient levels of these 28 compounds are largely unknown, estimated exposures from emissions inventories and limited air monitoring suggest that aldehydes (especially acrolein and formaldehyde) and metals (especially nickel and chromium compounds) may have possible health risk indices sufficient for additional attention. Recommendations for research are presented regarding exposure monitoring and evaluation of biologic mechanisms controlling how these substances induce and exacerbate asthma. Authors Leikauf, G. D. Source Environmental Health Perspective, Vol. 110, Suppl. 4, pp.505-526. Publication Date 2002

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 99 Reference 33 Evaluation of Amyris Direct Sugar to Hydrocarbon (DSHC) Fuel Abstract This report documents an engine test and a combustor test performed by Pratt & Whitney (P&W) in the evaluation of a branched C15 farnesane paraffin for use as a jet fuel blending stock. The farnesane was produced by Amyris, Incorporated (Amyris) and Total S.A. (Total) using a direct sugar to hydrocarbon (DSHC) process. The work was performed under the Continuous Lower Energy, Emission, and Noise (CLEEN) program, Contract DTFAWA-10-C-00041. P&W Canada (P&WC) performed a PW615F engine test on a baseline Jet A and a 20%/80% fuel blend of Amyris Farnesane/Jet A. The objective was to determine the impact of Amyris Farnesane on engine performance, operability and emissions. The PW615F is a 1,460 pound thrust, two- spool turbo fan with a reverse-flow combustor and dual-channel full authority digital engine control. The engine tests were performed at the six performance points shown below. Specific Fuel Consumption (SFC), gaseous emissions: carbon monoxide (CO), unburned hydrocarbon (UHC), carbon dioxide (CO2), oxides of nitrogen (NOx), SN, and PM, through laser induced incandescence were measured at these six points: • Ground idle (GI) • 30 percent power • 50 percent power • 85 percent power • 93 percent power • 100 percent takeoff power (1,460 lbf thrust). No difference was observed in engine operability for the Amyris Farnesane fuel blend compared to that of the baseline Jet A-1 fuel. No negative impact was observed on SFC, gaseous emissions, SN, or PM. Inspection of fuel system components showed no adverse effects from operation on the farnesane fuel blend. Under the direction of P&WC, Université Laval performed tests on a single nozzle can combustor test section. Ground starts at 50, 0, -20, -30, and -40 °F and altitude relights at 15, 20, 25, 30, and 35 kft were performed. No starting differences or altitude relight lean boundary differences were observed. The rich limits were not achieved for the relights due to rig constraints. Authors Lew, L., Biddle, T., United Technologies Corporation Source Continuous Energy, Emissions and Noise (CLEEN) Program, East Hartford, CT Publication Date April 16, 2014

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 100 Reference 34 Influence of Fuel Composition, Engine Power, and Operation Mode on Exhaust Gas Particulate Size Distribution and Gaseous Emissions from a Gas Turbine Engine Abstract The impact of fuel composition, engine power (idle and full power) and operation mode (cold and hot idle) on the gaseous emissions, particle number and mass concentrations and size distributions from an aircraft APU was investigated. A re-commissioned Artouste MK113 APU engine was used. The engine was run at three operational modes: i.e. approximately 6 minutes at idle (cold idle) after stabilized from start, 6 minutes at full power and then returning to idle again (hot idle) for 6 minutes. All operating parameters of the engine were monitored and recorded. The engine exhaust particle measurements and gaseous emissions were taken at three operating modes. Five alternative fuels/blending components were tested and compared to neat conventional JetA1 fuel either in pure or blended forms. These fuels varied in their compositions in terms of H/C ratio, density and other properties. A SMPS with a NDMA was used to determine the number and mass concentration and size distribution of engine exhaust in the size range from 5 nm to 160 nm. The influence of fuel elemental ratio (H/C), engine power and cold/hot operation on particle number and mass size distribution was investigated. The results show that there was a good correlation between fuels H/C ratio and particle concentrations, particle size and distributions characteristics. The engine at hot idle produced ∼20% less particles compare to the results at cold idle. The alternative fuel blends produced less particles than JetA1 fuel. The testing fuels produced similar levels of NOx, slight reductions in CO and remarkable reductions in UHC compared to JetA1. Authors Li, H, et.al Source Proc. ASME Turbo Expo, GT2013- 94854 Publication Date 2013

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 101 Reference 35 Quantification of Aldehydes Emissions from Alternative and Renewable Aviation Fuels using a Gas Turbine Engine Abstract In this research three renewable aviation fuel blends including two HEFA blends and one Fatty Acids Ethyl Ester (FAE) blend with conventional Jet A-1 along with a GTL fuel have been tested for their aldehydes emissions on a small gas turbine engine. Three strong ozone formation precursors: formaldehyde, acetaldehyde and acrolein were measured in the exhaust at different operational modes and compared to neat Jet A-1. The aim is to assess the impact of renewable and alternative aviation fuels on aldehydes emissions from aircraft gas turbine engines so as to provide informed knowledge for the future deployment of new fuels in aviation. The results show that formaldehyde was a major aldehyde species emitted with a fraction of around 60% of total measured aldehydes emissions for all fuels. Acrolein was the second major emitted aldehyde species with a fraction of ∼30%. Acetaldehyde emissions were very low for all the fuels and below the detention limit of the instrument. The formaldehyde emissions at cold idle were up to two to threefold higher than that at full power. The fractions of formaldehyde were 6–10% and 20% of total hydrocarbon emissions in ppm at idle and full power respectively and doubled on a g kg−1-fuel basis. Authors Li, Hu, Altaher, Mohamed A., Wilson, Chris W., Blakey, Simon, Chung, Winson, Rye, Lucas. Source Atmospheric Environment, Vol. 84, pp.373-379 Publication Date 2014

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 102 Reference 36 Comparison of PM Emissions from a Commercial Jet Engine Burning Conventional, Biomass, and Fischer- Tropsch Fuels Abstract Rising fuel costs, an increasing desire to enhance security of energy supply, and potential environmental benefits have driven research into alternative renewable fuels for commercial aviation applications. This paper reports the results of the first measurements of PM emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and, Fischer–Tropsch (F-T)-based fuels. PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1, and are attributed to fuel properties associated with the fuels and blends studied. Although the alternative fuel candidates studied in this campaign offer the potential for large PM emissions reductions, with the exception of the 50% blend of F-T fuel, they do not meet current standards for aviation fuel and thus cannot be considered as certified replacement fuels. Over the ICAO Landing Takeoff Cycle, which is intended to simulate aircraft engine operations that affect local air quality, the overall PM number-based emissions for the 50% blend of F-T fuel were reduced by 34 ± 7%, and the mass-based emissions were reduced by 39 ± 7%. Authors Lobo, P., Hagen, D., Whitefield, P. Source Environmental Science & Technology, Vol. 45, pp.10744-10749 Publication Date 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 103 Reference 37 Evaluation of Non-volatile Particulate Matter Emission Characteristics of an Aircraft Auxiliary Power Unit with Varying Alternative Jet Fuel Blend Ratios. Energy and Fuels Abstract The aviation industry is increasingly focused on the development of sustainable alternative fuels to augment and diversify fuel supplies while simultaneously reducing its environmental impact. The impact of airport operations on local air quality and aviation-related greenhouse gas emissions on a life-cycle basis have been shown to be reduced with the use of alternative fuels. However, the evaluation of incremental variations in fuel composition of a single alternative fuel on the production of nonvolatile PM (nvPM) emissions has not been explored. This is critical to understanding the emission profile for aircraft engines burning alternative fuels and the impact of emissions on local air quality and climate change. A systematic evaluation of nvPM emissions from a GTCP85 aircraft APU burning 16 different blends of used cooking oil (UCO)-derived hydroprocessed esters and fatty acids (HEFA) -type alternative fuel with a conventional Jet A-1 baseline fuel was performed. The nvPM number- and mass-based EI for the 16 fuel blends and neat UCO–HEFA fuel were compared against those for the baseline Jet A-1 fuel at three APU operating conditions. The large data set from this study allows for the correlation between fuel composition and nvPM production to be expressed with greater confidence. The reductions in nvPM were found to be greater with increasing fuel hydrogen content (higher proportion of UCO– HEFA in the fuel blend). For a 50:50 blend of UCO–HEFA and Jet A-1, which would meet current ASTM specifications, the average reduction in nvPM number-based emissions was ∼35%, while that for mass- based emissions was ∼60%. The nvPM size distributions were found to narrow and shift to smaller sizes as the UCO–HEFA component of the fuel blend increased. This shift has a greater impact on the reduction in nvPM mass compared to the overall decrease in the nvPM number when comparing the UCO–HEFA fuel blends to the baseline Jet A-1. Authors Lobo, P., Christie, S., Khandelwal, B., Blakey, S.G., Raper, D.W. Source Energy and Fuels, Vol. 29, pp.7705- 7711 Publication Date October 16, 2015

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 104 Reference 38 Influence of Jet Fuel Composition on Aircraft Engine Emissions: A Synthesis of Aerosol Emissions Data from the NASA APEX, AAFEX, and ACCESS Missions Abstract We statistically analyze the impact of jet fuel properties on aerosols emitted by the NASA Douglas DC-8 (Tail No. N817NA) CFM56-2-C1 engines burning 15 different aviation fuels. Data were collected for this single engine type during four different, comprehensive ground tests conducted over the past decade, which allow us to clearly link changes in aerosol emissions to fuel compositional changes. It is found that the fuel aromatic and sulfur content most affect the volatile aerosol fraction, which dominates the variability (but not necessarily the magnitude) of the number and volume EIs over all engine powers. Meanwhile, the naphthalenic content of the fuel determines the magnitude of the nonvolatile number and volume EI as well as the BC mass EI. Linear regression coefficients are reported for each aerosol EI in terms of these properties, engine fuel flow rate, and ambient temperature and show that reducing both fuel sulfur content and naphthalenes to near-zero levels would result in roughly a 10-fold decrease in aerosol number emitted per kilogram of fuel burned. This work informs future efforts to model aircraft emissions changes as the aviation fleet gradually begins to transition towards low-aromatic, low- sulfur alternative jet fuels from bio-based or Fischer–Tropsch production pathways. Authors Moore, R.H., Shook, M., Beyersdorf, A., Corr, C., Herndon, S., Knighton, W.B., Miake-Lye, R., Thornhill, K.L., Winstead, E.L., Yu, Z., Ziemba, L.D., Anderson, B.E. Source Energy and Fuels, Vol. 29, pp.2591- 2600 Publication Date February 25, 2015

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 105 Reference 39 Biofuel Blending Reduces PM Emissions from Aircraft Engines at Cruise Conditions Abstract Aviation-related aerosol emissions contribute to the formation of contrail cirrus clouds that can alter upper tropospheric radiation and water budgets, and therefore climate(1). The magnitude of air-traffic-related aerosol-cloud interactions and the ways in which these interactions might change in the future remain uncertain(1). Modeling studies of the present and future effects of aviation on climate require detailed information about the number of aerosol particles emitted per kilogram of fuel burned and the microphysical properties of those aerosols that are relevant for cloud formation(2). However, previous observational data at cruise altitudes are sparse for engines burning conventional fuels2,3, and no data have previously been reported for biofuel use in-flight. Here we report observations from research aircraft that sampled the exhaust of engines onboard a NASA DC-8 aircraft as they burned conventional Jet A fuel and a 50: 50 (by volume) blend of Jet A fuel and a biofuel derived from Camelina oil. We show that, compared to using conventional fuels, biofuel blending reduces particle number and mass emissions immediately behind the aircraft by 50 to 70 per cent. Our observations quantify the impact of biofuel blending on aerosol emissions at cruise conditions and provide key microphysical parameters, which will be useful to assess the potential of biofuel use in aviation as a viable strategy to mitigate climate change. Authors Moore, et al. Source Nature 21420, doi:10.1038 Publication Date March 16, 2017

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 106 Reference 40 Comparative Evaluation of Semi-Synthetic Jet Fuels (FT-SPK) Abstract This report compares the properties and characteristics of five blends of individual SPKs with petroleum-based Jet A, Jet A-1 or JP-8 fuel to make semi-synthetic jet fuels (SSJF). The study was requested by the aviation fuel community to provide technical support for the acceptance of SPK derived from synthesis gas as blending streams up to 50%(v) in fuel specifications for aviation turbine fuel. The methodology for comparison was to be the properties and characteristics used in the original evaluation of the Sasol SSJF which has experienced 9 years of successful service since it was approved for use as commercial jet fuel by DEF STAN 91-91 in 1998. The SPK used by Sasol in the original SSJF was produced by a Fischer–Tropsch (F-T) process using synthesis gas derived from coal. The synthesis gases for the four new candidates were produced from natural gas. The details of the F-T process conditions and the downstream processing differed among the five SPK fuels. Although all five SPK fuels were comprised almost entirely of saturated hydrocarbons, i.e., normal, iso-, and cyclo-paraffins, there were distinct differences in the ratio of the three families and in the distribution of carbon numbers. Despite these differences, when blended at 50%(v) with conventional jet fuels, these five SPK fuels produced SSJFs that were very similar to each other and had fit-for-purpose properties and characteristics that were very typical of conventional jet fuel. Moreover, all five SPKs met all of the requirements of Table 1 with the exception of density. It is important to realize there are no new chemical compositions involved in SSJF, just a change in the ratios of the aromatics to the saturates, i.e., the paraffin families. It is believed that these five fuels covered a large range of SPK compositions likely to result from F-T catalysis of synthesis gas based on the ratios of the paraffin families and the variation in the range of carbon numbers. It is concluded that semi- synthetic kerosenes produced by blending conventional jet fuels with up to 50%(v) SPK derived from synthesis gas by F-T catalysis and downstream processing and having compositions similar to that described in this report are fit-for-purpose as jet fuel. This conclusion has been validated by nine years of operation on one SSJF and in-depth flight-testing and test experience in ground support systems on another two of the five SSJFs evaluated here. Based on the property data of the five SPKs evaluated, it was possible to develop a composition and performance based definition of SPK derived from synthesis gas through an F-T process that would assure that SSJF with up to 50%(v) such SPK would be fit-for-purpose as jet fuel and certifiable under major fuel specifications. This definition is based on meeting a modification of Table 1 requirements designed to assure that the producer has control over the processes for making SPK and to assure a minimum quality of product, both as an item of commerce and for making SSJF. Authors Moses, C.A. Source Final Report, Coordinating Research Council, Inc., Universal Technology Corporation, CRC project No. AVI 2I04a, Alpharetta, GA Publication Date September 2008

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 107 Reference 41 Evaluation of Synthesized Aromatics Co-Produced with Iso-Paraffinic Kerosene for the Production of Semi- Synthetic Jet Fuel (SKA) Abstract This report compares the properties and characteristics of a Synthesized Kerosene containing Aromatics (SKA) with those of approved Synthesized Paraffinic Kerosenes (SPK) and petroleum-based jet fuels. Specifically, the SKA is produced by adding a benzene-rich stream to the UOP Cat-Poly™ reactor that converts C3 and C4 olefins into Sasol’s Iso- Paraffinic Kerosene (IPK). The benzene is alkylated to single-ring aromatics along with the production of the IPK. The result is IPK plus 15 to 20% single-ring aromatics and is termed IPK/A, which in turn belongs to the larger class of SKAs. Chemically, IPK/A differs from the original Sasol IPK only by the presence of the aromatics, and IPK/A meets all the requirements of ASTM D7566 Annex A1 defining acceptable SPKs from F-T products with the exception of the presence of the aromatics and a higher density due to those aromatics. Data are presented showing that the aromatics in IPK/A are all single-ring compounds distributed over several carbon numbers and many isomers. Moreover, detailed chemical analysis shows that the specific aromatics present in IPK/A are also in conventional jet fuels, so chemically, IPK/A is typical of conventional fuels. The results of the D4054 fit-for-purpose evaluation demonstrate that IPK/A by itself, i.e., unblended, has properties and characteristics that are typical of conventional jet fuels. The presence of the aromatics is not detrimental to any of the fit-for-purpose properties and characteristics. The density of IPK/A is greater than that of IPK and other SPKs due to the presence of the aromatics, thus making IPK/A more like conventional jet fuel than the F-T SPKs that have been generically approved by D7566. Note: New results are presented for materials compatibility tests on additional elastomers that were requested by the engine and airframe OEMs following the review of the earlier version of this report. Also, new data for specific heat, thermal conductivity, and water solubility have been added, all from improved test procedures. Finally, a 50/50 blend of IPK/A with conventional Jet A-1 meets all the D7566 Table 1 property requirements for turbine fuels containing synthesized hydrocarbons. Sasol IPK/A described in this report is one example of a F-T synthesized paraffinic kerosene to which have been added aromatics synthesized by the alkylation of light mono-aromatics, primarily benzene. Technically the results would be the same if alkylated mono-aromatics were added to any F-T paraffinic kerosene approved by D7566 Annex 1. A new annex is proposed for D7566 for the more general case of F-T kerosenes containing aromatics synthesized by the alkylation of mono-aromatics (FT-SPK/A) rather than limiting the annex to the Sasol IPK/A product. This new annex will follow the precedence of Annex A1 (FT-SPK). FT- SPK/A would be blended up to 50% with conventional jet fuel under the same conditions and restrictions as those of the SPKs already approved in Annex A1. Other restrictions requested by the aviation fuels community are also presented in this report. Suggested wording for the proposed Annex are provided. Authors Moses, C. Source Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, Subcommittee D02.J0 on Aviation Fuels, Section D02.J0.06 on Emerging Turbine Fuels, Research Report D02-1810, ASTM International, West Conshohocken, PA Publication Date November 1, 2015 No link is publicly available for this document. Access must be requested. Contact Link: https://www.astm.org/CONTACT/

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 108 Reference 42 Evaluation of Synthesized Iso-Paraffins Produced from Hydroprocessed Fermented Sugars (SIP Fuels) Abstract Total and Amyris are producing, from biomass, a farnesane aviation grade that is a high quality hydrocarbon grade. Data was collected in order to demonstrate the use of farnesane as a renewable component to be blended in jet fuel. This research report proposes a new annex for ASTM D7566, Standard Specifications for Aviation Turbine Fuels Containing Synthesized Hydrocarbons which defines specifications (detailed batch requirements) for the farnesane aviation grade to be used as a blending component in conventional jet fuel at an incorporation rate up to 10 vol. %. In support of the inclusion of this new annex in ASTM D7566, the typical composition and bulk physical and performance properties of farnesane was investigated on the basis of the property tables A1.1 & A2.1 and A1.2 & A.2.2 outlined in ASTM D7566-12, Annexes A1 and A2. In addition, farnesane-containing fuels at an incorporation rate up to 20 vol. % were extensively analyzed on the basis of the property Table 1 outlined in ASTM D7566-12 and the fit-for- purpose property Table 1 outlined in ASTM D4054, standard Practice for Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives. Farnesane-containing fuels are termed “Synthesized Iso- Paraffins produced from Hydroprocessed Fermented Sugars” (SIP fuels) and have been developed under the ASTM Task Force “Direct Sugar to Hydrocarbons” (DSHC). Total and Amyris produce at industrial scale farnesene (branched C15 molecules containing four double bonds) by fermentation of sugars. Through a combination of hydroprocessing and fractionation steps, farnesene is converted into farnesane (branched C15 paraffin) as a high quality hydrocarbon grade composed of nearly 100 wt. % of carbon and hydrogen. Such grade contains more than 98 wt. % of saturated hydrocarbons, less than 0.1 wt. % of aromatics and less than 1.5 wt. % of hexahydrofarnesol, a low polar branched C15 alcohol. Olefins are present in traces (typically less than 0.2 wt. %). Non- hydrocarbon compositions of this grade is in accordance with the maximum concentration limits defined for nitrogen, water, sulfur, metals and halogens in Synthesized Iso- Paraffinic Kerosene grades as per ASTM D7566-12, Annex A1, Table A1.2 and Annex A2, Table A2.2. Bulk physical and performance properties of blends of farnesane from 5 vol. % up to 20 vol. % into fossil Jet A-1 fuel satisfy the requirements outlined in ASTM D7566-12. Fit-for-purpose data from SIP fuels at incorporation rates of 10 vol. % and 20 vol. % are in the typical range of aviation turbine fuels containing synthesized hydrocarbons as defined in ASTM D4054-09. In particular, due to its intrinsic and unique properties (high thermal stability above 355°C, low freezing point below -60°C and high neat heat of combustion above 43.5 MJ/kg), farnesane improves the properties of the jet fuel it is blended with. Complementary data on the impact of the incorporation rate of 10 vol. % of farnesane on various conventional jet fuels representative of the industry as well as of the incorporation rate up to 50 vol. % are also presented. In addition, this research report includes data from engine ground tests conducted by Snecma and Lufthansa and from APU and combustor rig tests conducted by Honeywell using 10 vol. % and 20 vol. % farnesane, and the description of three test flights conducted by Airbus and CFM, and by Etihad and Boeing. In light of the results described in this report, Total Authors Roland, O., Garcia, F., TOTAL New Energies, Amyris, Inc., U.S. Air Force Research Laboratory Source Final Version (3.). Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, Subcommittee D02.J0 on Aviation Fuels, Research Report D02- 1776, ASTM International, West Conshohocken, PA Publication Date June 15, 2014 No link is publicly available for this document. Access must be requested. Contact Link: https://www.astm.org/CONTACT/

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 109 Evaluation of Synthesized Iso-Paraffins Produced from Hydroprocessed Fermented Sugars (SIP Fuels) and Amyris are pursuing the ASTM approval for the use of jet fuel containing farnesane at an incorporation rate up to 10 vol. % and the inclusion of the proposed new annex that defines and controls the farnesane aviation grade.

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 110 Reference 43 Estimation and Comparison of Particle Number Emission Factors for Petroleum-based and Camelina Biofuel Blends used in a Honeywell TFE-109 Turbofan Engine Abstract The experiments to estimate the total PM emissions factors for three types of fuels used in a high bypass turbofan engine were conducted at the National Testing Facility for Aerospace Fuels (NaTeF) during April 2014. The purpose of the study was to determine whether the PM emissions factors for biofuel blends would be lower compared to those of traditional Jet A fuel at four different engine power settings. The study investigated the number-based emissions factors (EIn) of total PM emissions in the exhaust stream out of a Honeywell TFE-109 turbofan engine as functions of engine thrust settings and fuel composition. Three types of fuels were tested on the engine and analyzed. The fuels were 100% Jet A, 75% Jet A-25% Camelina blend, and a 50% Jet A – 50% Camelina blend. The PM emissions, for each type of fuel, were sampled 1 meter from the engine exhaust plane while the engine was being operated. The TFE-109 turbofan engine was operated to run at four (4) engine power settings which were 10%, 30%, 85%, and 100% engine power settings. The study focused on estimating total PM EIn. The EIn for the 50% Jet A – 50% Camelina biofuel blend at 10% and 30% engine power settings were significantly lower compared to the PM EIn of Jet A fuel. The average EIn for all fuels, at all the observed four engine settings, were estimated to range between 1(10)15 and 1016 particles per kilogram of fuel. Authors Shila, Jacob J., and Johnson, Mary E. Source AIAA SciTech Forum, 54th AIAA Aerospace Sciences Meeting, San Diego, California Publication Date January 4-8, 2016

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 111 Reference 44 Alternate-fueled Combustor-sector Performance: Part A: Combustor Performance Part B: Combustor Emissions Abstract Alternate aviation fuels for military or commercial use are required to satisfy MIL-DTL-83133F or ASTM D 7566 standards, respectively, and are classified as “drop-in’’ fuel replacements. To satisfy legacy issues, blends to 50% alternate fuel with petroleum fuels are acceptable. Adherence to alternate fuels and fuel blends requires “smart fueling systems’’ or advanced fuel-flexible systems, including combustors and engines, without significant sacrifice in performance or emissions requirements. This paper provides preliminary performance and emissions and particulates combustor sector data. The data are for nominal inlet conditions at 225 psia and 800°F (1.551 MPa and 700 K), for SPK -type FT fuel and blends with JP-8+100 relative to JP-8+100 as baseline fueling. Assessments are made of the change in combustor efficiency, wall temperatures, emissions, and luminosity with SPK of 0%, 50%, and 100% fueling composition at 3% combustor pressure drop. The performance results (Part A) indicate no quantifiable differences in combustor efficiency, a general trend to lower liner and higher core flow temperatures with increased FT fuel blends. In general, emissions data (Part B) show little differences, but, with percent increase in FT-SPK-type fueling, particulate emissions and wall temperatures are less than with baseline JP-8. High-speed photography. Authors Shouse, D.T., Neuroth, C., Hendricks, R.C., Lynch, A., Frayne, C.W., Stutrud, J.S., Corporan, E., Hankins, T. Source ISROMAC13-2010-49 Publication Date 2010

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 112 Reference 45 Black Carbon Emissions Reductions from Combustion of Alternative Jet Fuels Abstract Recent measurement campaigns for alternative aviation fuels indicate that BC emissions from gas turbines are reduced significantly with the use of alternative jet fuels that are low in aromatic content. This could have significant climate and air quality-related benefits that are currently not accounted for in environmental assessments of alternative jet fuels. There is currently no predictive way of estimating aircraft BC emissions given an alternative jet fuel. We examine the results from available measurement campaigns and propose a first analytical approximation (termed ‘ASAF’) of the BC emissions reduction associated with the use of paraffinic alternative jet fuels. We establish a relationship between the reduction in BC emissions relative to conventional jet fuel for a given aircraft, thrust setting relative to maximum rated thrust, and the aromatic volume fraction of the (blended) alternative fuel. The proposed relationship is constrained to produce physically meaningful results, makes use of only one free parameter and is found to explain a majority of the variability in measurements across the engines and fuels that have been tested. Authors Speth, R.R., Rojo, C., Malina, R., Barrett, S.R.H. Source Atmospheric Environment, Vol. 105, pp.37-42 Publication Date January 19, 2015

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 113 Reference 46 Impact of Aviation Non-CO2 Combustion Effects on the Environmental Feasibility of Alternative Jet Fuels Abstract Alternative fuels represent a potential option for reducing the climate impacts of the aviation sector. The climate impacts of alternatives fuel are traditionally considered as a ratio of life-cycle greenhouse gas (GHG) emissions to those of the displaced petroleum product; however, this ignores the climate impacts of the non-CO2 combustion effects from aircraft in the upper atmosphere. The results of this study show that including non-CO2 combustion emissions and effects in the life cycle of a SPK fuel can lead to a decrease in the relative merit of the SPK fuel relative to conventional jet fuel. For example, an SPK fuel option with zero life-cycle GHG emissions would offer a 100% reduction in GHG emissions but only a 48% reduction in actual climate impact using a 100- year time window and the nominal climate modeling assumption set outlined herein. Therefore, climate change mitigation policies for aviation that rely exclusively on relative well-to-wake life-cycle GHG emissions as a proxy for aviation climate impact may overestimate the benefit of alternative fuel use on the global climate system. Authors Stratton, R.W., Wolfe, P.J., Hileman, J.I. Source Environmental Science & Technology, Vol. 45, Issue 24, pp.10736-10743 Publication Date November 22, 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 114 Reference 47 Combustion Products of Petroleum Jet Fuel, a Fischer-Tropsch Synthetic Fuel, and a Biomass Fatty Acid Methyl Ester Fuel for a Gas Turbine Engine Abstract We report combustion emissions data for several alternatives to petroleum-based Jet A jet fuel, including a natural gas-derived Fischer– Tropsch (FT) synthetic fuel; a 50/50 blend of the FT synthetic fuel with Jet A-1; a 20/80 blend of a fatty acid methyl ester (FAME) with jet fuel; and a 40/60 blend of FAME with jet fuel. The chief distinguishing features of the alternative fuels are reduced (for blends) or negligible (for pure fuels) aromatic content and increased oxygen content (for FAME blends). A CFM International CFM56-7 gas turbine engine was the test engine, and we measured NOX, CO, speciated volatile organic compounds (including oxygenates, olefins, and aromatic compounds), and nonvolatile particle size distribution, number, and mass emissions. We developed several new methods that account for fuel energy content and used the new methods to evaluate potential fuel effects on emissions performance. Our results are categorized as follows: (1) regulated pollutant emissions, CO, and NOX; (2) volatile organic compound emissions speciation; and (3) particle emissions. Replacing all or part of the petroleum jet fuel with either FAME or FT fuel reduces NOX emissions and may reduce CO emissions. Combustion of FT fuel and fuel blends increases selectivities and in some cases yields of oxygenates and some hydrocarbon volatile organic compound emissions relative to petroleum jet fuel. Combustion of FAME fuel increases propene and butene emissions, but despite its oxygen content does not strongly affect oxygenate emissions. Replacing petroleum jet fuel with zero aromatic alternatives decreases the emissions of aromatic hydrocarbons. The fuel effects become more pronounced as the size of the aromatic molecule increases (e.g., toluene is reduced more strongly than benzene). Particle emissions are decreased in particle size, number density, and total mass when petroleum jet fuel is replaced with the zero aromatic fuels. The effects of fuel composition on particle emissions are most pronounced at lower power conditions, i.e., when combustion temperature and pressure are lower, and less efficient mixing may lead to locally higher fuel/air ratios than are present at higher power. Authors Timko, M.T., Herndon, S.C., de la Rosa Blanco, E., Wood, E.C., Yu, Z., Miake-Lye, R.C., Knighton, W.B., Shafer, L., DeWitt, M.J., Corporan, E. Source Combustion Science and Technology, Vol. 183, pp.1039-1068 Publication Date April 13, 2011

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 115 Reference 48 Insights into the Combustion Chemistry Within a Gas-Turbine Driven Auxiliary Power Unit as a Function of Fuel Type and Power Level using Soot Nanostructure as a Tracer Abstract Particulate emissions were collected from an APU directly upon TEM grids for particle characterization by HRTEM. Carbonaceous emissions from two fuels, a coal-based Fischer–Tropsch and standard JP-8 were compared, each at three power levels. Differences in soot nanostructure, specifically fullerenic content reveal changes in the combustion chemistry with engine power level, as do differences in aggregate size between the two fuels. As inferred from the soot nanostructure, comparison between fuels demonstrates the impact of fuel structure upon soot formation chemistry. Authors Wal, V., Bryg, R.L., Victoria M., Huang, C-H Source Fuel Vol. 115, pp.282–287 Publication Date 2014

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 116 Reference 49 Effects of Bio-Derived Fuels on Emissions and Performance Using a 9-Point Lean Direct Injection Low Emissions Concept Abstract A 9-Point Lean Direct low emissions combustor concept was utilized to evaluate gaseous emissions performance of two bio-derived alternative jet fuels and a JP-8 fuel for comparison. Gaseous emissions were measured in a flame tube operating at inlet temperatures from 650 up to 1030 F, pressures of 150, 250, and 350 psia, and a range of fuel/air ratios. The alternative fuels consisted of a Hydroprocessed Esters and Fatty Acids Fuel made from tallow and a second bio-derived fuel produced from direct fermentation of sugar. Authors Wey, C., and Bulzan, D. Source Proc. ASME Turbo Expo, GT2013- 94888 Publication Date 2013

Emissions Quantification Methodology Report: ACRP 02-80 Quantifying Emissions Reductions at Airports from the Use of Alternative Jet Fuel Emissions Quantification Methodology Report Page 117 Reference 50 The Impact of Advanced Biofuels on Aviation Emissions and Operations in the U.S. Abstract We analyze the economic and emissions impacts on U.S. commercial aviation of the Federal Aviation Administration’s renewable jet fuel goal when met using advanced fermentation (AF) fuel from perennial grasses. These fuels have recently been certified for use in aircraft and could potentially provide greater environmental benefits than aviation biofuels approved previously. Due to uncertainties in the commercialization of AF technologies, we consider a range of assumptions concerning capital costs, energy conversion efficiencies and product slates. In 2030, estimates of the implicit subsidy required to induce consumption of AF jet fuel range from $0.45 to $20.85 per gallon. These correspond to a reference jet fuel price of $3.23 per gallon and AF jet fuel costs ranging from $4.01 to $24.41 per gallon. In all cases, as renewable jet fuel represents around 1.4% of total fuel consumed by commercial aviation, the goal has a small impact on aviation operations and emissions relative to a case without the renewable jet fuel target, and emissions continue to grow relative to those in 2005. Costs per metric ton of carbon dioxide equivalent abated by using biofuels range from $42 to $652. Authors Winchester, N., Malina, R., Staples, M.D., Barrett, S.R.H. Source Energy Economics, Vol. 49, pp.482- 491 Publication Date April 8, 2015

ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report Get This Book
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One of the most challenging environmental issues facing the aviation industry today is the impact of jet fuel emissions on the global climate. The use of sustainable alternative jet fuels (SAJF) to reduce aircraft emissions will become significantly more important in coming years. Capturing the air quality benefits in a way that is useful to airports requires understanding how SAJF reduce pollutant emissions, quantifying the reduction, and demonstrating the impact through an easy-to-use tool that airports can apply to their emissions inventories.

ACRP Web-Only Document 41: Alternative Jet Fuels Emissions: Quantification Methods Creation and Validation Report represents the second phase of this ACRP work. The first phase provided an understanding of how SAJF impacts aircraft emissions. This phase analyzes the data compiled in the report to quantify SAJF emission impacts.

Results of this analysis were subsequently used to develop a simplified tool that will allow airports to easily estimate emission reductions from use of SAJF at their airport. The Alternative Jet Fuel Assessment Tool and the Sustainable Alternative Jet Fuels and Emissions Reduction Fact Sheet are the two key products from ACRP 02-80.

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