Characteristics of sub-10 nm particle emissions from in-use commercial aircraft observed at Narita International Airport

Nobuyuki Takegawa,Yuji Fujitani,Kentaro Misawa,Akihiro Fushimi,Katsumi Saitoh,Hiromu Sakurai,Yoshiko Murashima

doi:10.5194/acp-21-1085-2021

Abstract

Abstract. The characterization of ultrafine particle emissions from jet aircraft equipped with turbofan engines, which are commonly used in civil aviation, is an important issue in the assessment of the impacts of aviation on climate and human health. We conducted field observations of aerosols and carbon dioxide (CO2) near a runway at Narita International Airport, Japan, in February 2018. We used an ultrafine condensation particle counter (UCPC) and a condensation particle counter (CPC) with unheated and 350 ∘C heated operation modes to investigate the contributions of sub-10 nm size ranges to the total and the non-volatile particle number concentrations. The performance of the 350 ∘C heated mode was tested in the laboratory to verify the consistency with existing methods for non-volatile particle measurements. We also used a scanning mobility particle sizer with unheated and 350 ∘C heated modes and an engine exhaust particle sizer for the measurements of particle number size distributions. Spiked increases in the particle number concentrations and CO2 mixing ratios were observed to be associated with the directions of wind from the runway, which can be attributed to diluted aircraft exhaust plumes. We estimated the particle number emission indices (EIs) for discrete take-off plumes using the UCPC, CPC, and CO2 data. The median values of the total and the non-volatile particle number EIs for diameters larger than 2.5 nm as derived from the UCPC data were found to be 1.1×1017 and 5.7×1015 kg per fuel, respectively. More than half the particle number EIs were in the size range smaller than 10 nm for both the total and the non-volatile particles in most of the cases analyzed in this study. The significance of sub-10 nm size ranges for the total particles in the diluted plumes was qualitatively consistent with previous studies, but that for the non-volatile particles was unexpected. Possible factors affecting the similarities and differences compared with the previous findings are discussed.

Highlights

Civil aviation has grown rapidly as a result of global economic development
The detection efficiencies for the ultrafine condensation particle counter (UCPC) and condensation particle counter (CPC) were empirically estimated by using our previous calibration results for the CPC (Takegawa and Sakurai, 2011), the manufacturer specifications for the UCPC (Takegawa et al, 2017), and the penetration efficiencies in the instrument and the sampling lines
We found a good agreement between the experimental data and the estimated detection efficiencies for both the UCPC and CPC

Summary

Introduction

The impacts of aircraft emissions on climate and human health have been recognized as an important issue (ICAO, 2017; Masiol and Harrison, 2014; Stacey, 2019; and references therein). The primary importance of aviation-produced aerosol particles in assessing the climate impacts is the formation of contrail cirrus clouds from soot or black carbon (BC) emitted at aircraft cruising altitudes (Kärcher and Voigt, 2017; Kärcher, 2018). Aircraft emissions can significantly affect the number concentrations of Aitken mode particles in the upper troposphere (Wang et al, 2000; Lee et al, 2010; Righi et al, 2013, 2016). Aircraft emissions can significantly affect the number concentrations of Aitken mode particles in the upper troposphere (Wang et al, 2000; Lee et al, 2010; Righi et al, 2013, 2016). Righi et al (2013, 2016)

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