AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Particle Emissions from In-use Commercial Aircrafts Observed at the Narita International Airport
NOBUYUKI TAKEGAWA, Kentaro Misawa, Akihiro Fushimi, Yoshiko Murashima, Hiromu Sakurai, Tokyo Metropolitan University
Abstract Number: 419 Working Group: Combustion
Abstract Jet-engine aircrafts are important sources of ultrafine aerosol particles in the atmosphere. Intensive measurements of aerosols and combustion tracer gases (carbon dioxide (CO2) and nitrogen oxides) were conducted at an observation point ~140 m from the major runway of the Narita international airport, Japan between February 7 and 23, 2018. The number concentrations of aerosol particles with diameters larger than 2.5 nm (N2.5, TSI-UCPC3776), those larger than 10 nm (N10, TSI-CPC3771), and mixing ratio of CO2 are used to estimate the effective particle number emission factors from in-use commercial aircrafts under real-world operating conditions. The inlet tube for the UCPC and CPC was switched between unheated (room temperature) and heated (350 degrees C) modes every 8 h. The sampling method for heated N10 corresponds to the standard procedure for aircraft engine exhaust measurements (SAE AIR6241). The consistency between our measurements and the standard procedure was tested in the laboratory before and after the intensive observation period. Except for specific time slots with frequent aircraft traffics at the runway, we successfully identified isolated plumes from individual aircrafts based on spiked increases in CO2 (>100 plumes both for unheated and heated modes). A comparison between unheated or heated N2.5 and N10 in those plumes indicates that the particle number emissions were dominated by volatile particles with diameters smaller than 10 nm. For some selected cases, the observed plumes were further classified into take-off and landing events based on detailed flight information provided by the airport. The sampling distances of the observed plumes were estimated using local wind data. Variability in the effective number emission factors is discussed in relation with the estimated sampling distances, landing/take-off cycles, and aircraft types. Similarities and differences between our results and earlier studies are also discussed.