; (4) the extent to which the use of preconditioned air during embarkation and disembarkation changes the likelihood of a passenger’s exposure to a pathogen as opposed to the use of air conditioning packs fed by the auxiliary power unit; and (5) other variables that determine the likelihood of an individual’s exposure to a pathogen on a passenger airplane, including the use or location of personal air outlets, seating location, load factor, movement of cabin crewmembers and passengers throughout the cabin during the flight, embarkation, and disembarkation, testing and replacement frequency of air filters, commonly touched surfaces, use or location of lavatories, and such other variables as the National Academies consider relevant. (c) Report to Congress Not later than 1 year after the date of enactment of this Act, the Administrator shall— (1) submit to the congressional committees of jurisdiction a report on the results of the study required under this section