Tracer study of airborne transmission in an aircraft cabin mock-up

This paper reports a study on the airborne transmission of the infectious disease(s) in the mock-up of a Boeing 767-300 aircraft cabin, using a tracer gas method with a high temporal resolution. Carbon dioxide was used as the tracer gas to simulate the pulse emitting such as coughing or sneezing of a sick passenger in a commercial aircraft. The net tracer concentration and a self-defined factor called the normalized cumulative factor (CF_N) were analyzed. A detailed description of the transient airborne transmission was obtained based on the contour maps of tracer gas propagation from its release source to other locations. The distance between the release source and the receptors, the location of the release source and the total air supply rates were varied, to investigate the dependence of airborne transmission on these factors. The results showed that the close proximity between the occupants increased the exposure risk, and that the location of the release source was an important factor affecting the airborne transmission. In real aircraft, one possible way to decrease the exposure risk of the infectious diseases would be to move the release source from the center to the sides or from the backseats to the front seats. This would facilitate discharging a larger portion of the airborne pollutants directly to the return air duct before they were spread to other locations in the aircraft cabin. Increasing the total air supply rate could also lower the exposure risk.