Experimental investigation of interpersonal particle transport in an aircraft cabin mockup with nanofiber air filters.

Improving aircraft environmental control systems could reduce the risk of airborne infectious disease transmission in aircraft cabins. The high-efficiency particulate air (HEPA) filters used in the existing systems exhibit high pressure drop, which results in high consumption of energy and fuel. Nanofiber air filters fabricated by electrospinning can reduce pressure drop, but their performance in aircraft cabins is unknown. Therefore, this study experimentally investigated the interpersonal particle transport in an aircraft cabin mockup with nanofiber air filters. First, a full-scale, fully occupied, 7-row, single-aisle aircraft cabin mockup was constructed. Nanofiber filtration units were fabricated using the electrospinning technique. Under the well-sealed laboratory testing conditions, both the small-scale nanofiber and HEPA filter media exhibited a particle removal efficiency of around 99 %. The performance of nanofiber and HEPA filtration units installed in the environmental control system of the mockup was then measured. Finally, the interpersonal particle transport in the cabin was measured. The results show that the particle removal efficiency of the nanofiber filtration units installed in the environmental control system ranged from 64 to 72 % when the particle size was 0.3-0.4 μm, which primarily reflected the large air leakages associated with the filter installation. At the filter media level, the pressure drop across the nanofiber units in the mockup was 61-67 % lower than that across the HEPA units under the same airflow rate, which however may not necessarily translate into lower pressure drop for actual filters in aircraft due to the potentially different design in terms of media face area. The average normalized particle concentration in the breathing zones of fellow passengers in the cabin mockup with the nanofiber filtration units was by 0.23, 0.29, and 0.32, respectively, when the index passenger was seated at the window, middle, and aisle.