Abstract No:
1712
Abstract Type:
Student Poster
Authors:
O Ezeifeka1, Y Nazarenko1
Institutions:
1University of Cincinnati, Cincinnati, OH
Presenter:
Onyinye Ezeifeka, MSc.
University of Cincinnati
Faculty Advisor:
Yevgen Nazarenko
University of Cincinnati
Description:
Aircraft ground operations produce particle emissions that contribute to occupational exposure for aviation workers. Combustion conditions during different operating modes influence particle formation and aerosol size distribution in engine exhaust.
Situation/Problem:
Limited experimental studies have compared particle emission characteristics across aircraft operating modes under controlled laboratory conditions. Understanding how operating regimes influence particle emissions is important for evaluating potential occupational exposure.
Methods:
Jet A fuel combustion was simulated in a laboratory-scale combustor under controlled conditions. Three representative operating states were approximated by adjusting the equivalence ratio (ϕ = 0.7, 1.0, 1.3, 1.6) while maintaining constant temperature (150 °C), chamber pressure (10 psig), and air flow rate (3.915 g/s). Exhaust was diluted with 30 L/min of air using a mass flow controller. Particle size distribution and number concentration were measured using a Fast Mobility Particle Sizer (FMPS), a Scanning Mobility Particle Sizer (SMPS), and an Optical Particle Sizer (OPS), enabling high-resolution characterization of particles in the nanometer/ultrafine and coarse size ranges. Results were compared across the three operating modes to examine differences in total particle number emissions and size distribution patterns. Particular attention was given to ultrafine particles (<100 nm), which are of interest in occupational health due to their ability to penetrate deep into the respiratory system. Statistical analysis was conducted to compare particle emissions across the 4 operating conditions. Analysis of variance (ANOVA) was used to test for overall differences among conditions, followed by post hoc multiple-comparison testing to identify specific pairwise differences.
Results / Conclusions:
The results show that particle emissions from Jet A combustion varied with combustion condition and the equivalent aircraft operating modes simulated in the combustor. Measurements from FMPS and SMPS indicate that emissions were dominated by ultrafine particles (<100 nm), particularly under the lean condition (ϕ = 0.7), which corresponds to idle-type engine operation. In this condition, particle concentrations were highest and remained elevated over time, with peaks in the 15–30 nm range, indicating strong nucleation-mode particle formation.
Under stoichiometric conditions (ϕ = 1.0), representing an intermediate operating regime similar to taxi or balanced combustion conditions, particle concentrations were substantially lower across most size bins. Richer conditions (ϕ = 1.3 and 1.6), which approximate high-power or takeoff-related regimes, showed variable but generally lower ultrafine particle concentrations compared with the lean condition.
OPS measurements showed that particles ≥0.3 µm were present at much lower concentrations than ultrafine particles, with most counts concentrated near 0.3 µm and very few particles larger than 1 µm.
These findings contribute to understanding emission variability across aircraft engine operating conditions and provide evidence that can inform future occupational exposure assessments and mitigation strategies in aviation environments. Overall, the results indicate that particle emissions are strongly influenced by combustion condition, with lean operating regimes producing the highest ultrafine particle concentrations. The dominance of ultrafine particles across conditions highlights the importance of considering nanoparticle exposure when evaluating health risks for aviation ground personnel and developing appropriate exposure control strategies.
Core Competencies:
Exposure Assessment
Secondary Core Competencies:
Chemical Sampling and Instrumental Analysis
Work Environments, Occupations, and Industrial Processes
Choose at least one (1), and up to five, (5) keywords from the following list. These selections will optimize your presentation's search results for attendees.
Aerosol and airborne particulate monitoring
Environmental protection and monitoring
Exposure Assessment
Real-time detection services and direct reading instruments
Based on the information that will be presented during your proposed session, please indicate the targeted audience practice level: (select one)
Professional: Professional is a job title given to persons who have obtained a baccalaureate or graduate degree in IH/OH, public health, safety, environmental sciences, biology, chemistry, physics, or engineering or who have a degree in another area that meets the standards set forth in the next section, Knowledge and Skill Sets of IH/OH Practice Levels, and has had 4 or more years of practice. One significant way of demonstrating professional competence is to achieve certification by a 3rd party whose certification scheme is recognized by the International Occupational Hygiene Association (IOHA) such as the Board of Global EHS Credentialing (BGC).
Was this session organized by an AIHA Technical Committee, Special Interest Group, Working Group, Advisory Group or other AIHA project Team?
No
Are worker exposure data and/or results of worker exposure data analysis presented?
No
How will this help advance the science of IH/OH?
This study helps advance Industrial Hygiene by providing controlled experimental data on particle emissions under different aircraft operating conditions. It shows how combustion regimes influence the size and concentration of particles that workers may inhale during ground operations. This improves understanding of exposure sources and supports better exposure assessment in aviation settings. The findings are also relevant as the industry transitions to sustainable aviation fuels (SAFs). Since SAFs have different chemical compositions than Jet A, baseline data from conventional fuel helps researchers compare emission profiles and evaluate whether cleaner fuels reduce worker exposure to harmful particles.
Have you presented this information before?
No
I have read and agree to these guidelines.
Yes