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Aircraft gas turbine engines produce Particulate Matter (PM) emissions that have been linked to human health and climate issues, leading to the introduction of regulatory sampling and measurement standards for nonvolatile PM (nvPM) by the International Civil Aviation Organization (ICAO). Due to the significant nvPM losses within the prescribed sampling systems, loss corrections are used. Currently, based on sampling assumptions, electrostatic losses are not included in the standardized loss tool, as it is estimated to account for less than 3% of the total nvPM loss. This study experimentally investigated electrostatic loss of unipolar, bipolar, and naturally charged salt, silver, and carbon black particles at sizes (4–150 nm) and through sampling tubes representative of aircraft nvPM sampling. A unipolar and bipolar charger, along with a tandem SMPS-CPC measurement methodology, were employed to explore the impacts of tube material, Reynolds Number, tube diameter, residence time, and particle charge state on electrostatic loss. Minimal electrostatic loss was measured for conductive stainless steel and extensively bedded-in (above 300 h) carbon-loaded PTFE. However, an additional loss of up to 50% was observed within new cPTFE (with approximately 30 min of bedding-in), attributed to precipitation in an electric field. Furthermore, it was found that electrostatic dispersion could cause significant additional losses at high concentrations of unipolar or bipolar asymmetrically charged particles. Therefore, further research is required to determine the charge state of aircraft nvPM across different aircraft engine conditions to determine if unquantified electrostatic loss could occur within the probe section of the sampling system. [ABSTRACT FROM AUTHOR]

Inboard and outboard particle number concentrations are reported from 12 flights from the FAAM BAe-146. The data show that the concentrations pre take off and post landing are dominated by external sources. The concentrations in the cabin are generally lower than outside and pre-take off peak after the doors have closed in 75% of cases. In flight cabin events were associated with either ingress of external particles, or particles generated by the airframe. The airframe events were sporadic in nature, and often associated with changing engine conditions. In over 50% of cases, in cabin particle events were observed on approach, with no increase in outboard concentrations. Supporting aerosol composition data showed that non-exhaust, non-airport sources also influence the cabin air quality, including the presence of lubrication oil. The average number concentration exposure was between 6800 and 10,800 cm−3 per flight and, during a fume event, the average organic mass concentration exposure was 5.85 µg m−3 for the flight. The mass concentration exposure and associated average concentration are below UK workplace exposure limits for non-hazardous dusts and PM10 24-h air quality standards. Copyright © 2021 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

The total climate, air quality, and health impact of aircraft black carbon (BC) emissions depend on quantity (mass and number concentration) as well as morphology (fractal dimension and surface area) of emitted BC aggregates. This study examines multiple BC emission metrics from a gas turbine with a double annular combustor, CFM56-5B4-2P. As a part of the SAMPLE III.2 campaign, concurrent measurements of particle mobility, particle mass, particle number concentration, and mass concentration, as well as collection of transmission electron microscopy (TEM) samples, allowed for characterization of the BC emissions. Mass- and number-based emission indices were strongly influenced by thrust setting during pilot combustion and ranged from <1 to 208 mg/kg-fuel and 3 ×× 1012to 3 ×× 1016particles/kg-fuel, respectively. Mobility measurements indicated that mean diameters ranged from 7 to 44 nm with a strong dependence on thrust during pilot-only combustion. Using aggregation and sintering theory with empirical effective density relationships, a power-law relationship between primary particle diameter and mobility diameter is presented. Mean primary particle diameter ranged from 6 to 19 nm; however, laser-induced incandescence (LII) and mass-mobility-calculated primary particle diameters demonstrated opposite trends with thrust setting. Similarly, mass-mobility-calculated aggregate mass specific surface area and LII-measured surface area were not in agreement, indicating both methods need further development and validation before use as quantitative indicators of primary particle diameter and mass-specific surface area. Copyright 2015 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]