Coupled Computational Fluid Dynamics–Agent-Based Modeling of Airborne and Fomite Infection Risk in Gate-to-Gate Air Travel

The COVID-19 pandemic exposed how vulnerable air travel is to infectious diseases and prompted stronger federal coordination and integrated research (Sun et al., 2022; GAO 2024). Boeing, the Federal Aviation Administration, Centers for Disease Control and Prevention, and National Research Council Canada formed a multidisciplinary team to tackle communicable disease challenges in aviation and enable rapid public health responses. This collaboration produced the Travel Risk In Pandemics (TRIP-X) framework to assess risk controls and evaluate mitigation strategies for different aviation and travel settings.

Here, we present the computational model architecture and methods used in TRIP X to simulate airborne and fomite transmission in a gate to gate air travel scenario. TRIP X combines agent based behavioral modeling, computational fluid dynamics (CFD), pathogen dispersion, and an epidemiological exposure–risk model. Uniquely, the framework couples steady-state airflow fields with dynamically relocating infectious sources and surface contact transfer within a stochastic agent movement model, enabling multi-pathway exposure assessment at high spatial and temporal resolution. The model supports integration of observational behavioral data, configurable mitigation measures, and screening scenarios.

By coupling airflow physics, movement behavior, and multi-pathway exposure modeling, TRIP-X reveals how ventilation, occupant dynamics, and surface interactions jointly shape infection risk distributions in transportation environments. The framework provides an uncertainty-aware basis for comparing mitigation strategies and demonstrates the importance of integrated modeling to capture exposure heterogeneity not resolved in single-domain approaches.