Comparison of Pathogens Dispersion in an Aircraft Cabin Using Gas Injection Source Versus a Coughing Manikin

The dispersion characteristics of airborne pathogens were investigated in a Boeing 767 mockup cabin containing 11 rows with 7 seats per row, using two tracer gas source methods: continuous injection at low velocity and a coughing manikin. Both the injection source and the coughing manikin were located on the same seat in the sixth row. The injection source utilized CO2 gas at an injection rate of 5.0 liters per minute mixed with helium at a rate of 3.07 liters per minute to neutralize buoyancy. The manikin coughed approximately once every 75 seconds, with a volume of 4.2 liters of CO2 per cough. To ensure sufficient data were collected at each sampling location, each coughing manikin test was run for 6 coughs and each injection source test for 30 minutes of continuous injection. In both test methods, the tracer gas concentration was measured using CO2 gas analyzers at seated passenger breathing height of 1.2 m and radially up to 3.35 m away from the gas injection location, representing approximately four rows of a standard B767 aircraft. The collected data obtained from each tracer method was then normalized to provide a suitable comparison basis that is independent of tracer gas introduction flowrate. The results showed that both tracer source methods gave similar dispersion trends in diagonal and lateral directions away from the injection location. However, the tracer gas concentration was higher along the longitudinal direction in the coughing manikin tests due to the cough momentum. The results of this work will help researchers analyze different experimental and numerical approaches used to determine contaminant dispersion in various environments and will provide a better understanding of the associated transport phenomena.