Composition and Sources of the Organic Particle Emissions from Aircraft Engines

Abstract

We report a positive matrix factorization (PMF) analysis of organic particulate material (PM) emissions of aircraft engine exhaust that includes data from five different aircraft engines and two different fuels (petroleum jet fuel and a Fischer-Tropsch fuel) collected over three field missions. PMF of aerosol mass spectrometer (AMS) data was used to identify six distinct factors: two lubrication oil factors, two aliphatic factors, an aromatic factor, and a siloxane factor. Of these, the lubrication oil factors and the siloxane factor were noncombustion sources. The siloxane factor was attributed to silicone tubing used in the sampling system deployed in one of the three missions included in this study, but not the other two. The two lubrication oil factors correlate with the two different lubrication oils used by the aircraft engines evaluated in this study (Mobil II and Air BP) as well as minor differences presumably due to variation in the blend stocks, temperature history, and analytical factors. Overall, the sum of the aliphatic and aromatic factors decreased with increasing power, as expected based on known trends in VOC emissions. The aliphatic #1 factor correlated with soot emissions, especially at power conditions where EI m -soot was greater than Received 26 June 2013; accepted 11 October 2013. The authors thank NASA for leading the APEX-3 and AAFEX measurement activities and for supporting our participation in AAFEX-1 (NRA # NNC07CB57C). FAA (via Missouri University of Science and Technology) supported our participation in AAFEX-2. NASA DAOF and Cleveland Hopkins Airport were gracious hosts for the field measurement campaigns. Discussions with Kathy Tacina, Chris Heath, Bruce Anderson, and Andreas Beyersdorf helped guide our analysis and discussion of our results. Scott Herndon's efforts made sure that Aerodyne's involvement in the APEX-3 and AAFEX campaigns were successful. Berk Knighton generously shared his PTR-MS benzene measurement data. Ezra Wood (APEX-3 and AAFEX) and Jon Franklin (AAFEX-2) were valuable team members who contributed to preparation, execution, and analysis efforts. John Jayne developed AMS operating procedures used in this study and advised the team during the data analysis effort.Address correspondence to Richard C. . The aliphatic factor #2 mass spectrum shared some similarities with ambient aerosol organic PM present during the tests and correlated most strongly with dilution levels, two observations that suggest that aliphatic #2 contains components found in ambient aerosol. The aromatic factor correlated with benzene emissions, especially at low power conditions were EI m -benzene was greater than 0.03 mg kg ?1 . Our results improve the current understanding of aircraft PM composition.

Peak-fitting and integration imprecision in the Aerodyne aerosol mass spectrometer: effects of mass accuracy on location-constrained fits

“…Zhang et al, 2007), or during source studies (e.g. Elsasser et al, 2013;Timko et al, 2014;Corbin et al, 2015a).…”

New Methodology for Quantifying Polycyclic Aromatic Hydrocarbons (PAHs) Using High-Resolution Aerosol Mass Spectrometry

“…Common practices were used to postcorrect the air beam (AB) to account for natural drift in the instrument sensitivity (Allan et al 2003b). As recommended by Timko et al (2009Timko et al ( , 2014, we have also removed signal contributions related to the contamination artifacts that arise from the fragmentation of aerosolized polydimethylsiloxane (SiO(CH 3 ) 2 ), found in conductive silicone tubing.…”

Chemistry characterization of jet aircraft engine particulate matter by XPS: Results from APEX III

“…Fuel aromatic content varied between 14.5% and 22.7% and sulfur content between 200-700 ppm depending upon the engine/aircraft particular test. Further details may be found in references [27,28]. For this same range the fuel hydrogen fraction varied between 0.137 and 0.147.…”

“…Timko et al reported significant organic content in PM sampled from idle conditions [26]. Recently both Timko et al [27] and Yu et al [9] found lubrication oil contribution to volatile PM. All such measurements were performed using the Aerodyne aerosol mass spectrometer.…”

“…For the ERJ and A300 jets, nvPM organic content exhibits the opposite trend: it is higher at higher powers. Here a possible explanation is that unburnt hydrocarbons in the exhaust stream could have condensed upon the surfaces of the nvPM at high power where volatile emissions are higher than at mid-power levels [27]. Yet the HRTEM images did not reveal an organic coating upon the nvPM particles nor any liquid-like droplets upon the TEM grid used for direct capturefor any of the soots.…”