Growing concern over the availability of Respiratory protective devices (eg, filtering facepiece Respirators), in the face of the probable extreme demand brought on by a pandemic influenza, has prompted the suggestion that useful life of N95 filtering facepiece Respirator can be extended by the concurrent use of a surgical mask as an outer protective barrier over the Respirator. Personal protective equipment generally places a strain on the user, and the detrimental physiological and psychological burdens normally imposed by Respirator use could be magnified by the addition of an extra layer of protection such as a surgical mask. The issue of this potentially increased burden of the concurrent use of a surgical facemask with an N95 filtering facepiece Respirator is investigated to afford users the necessary information to make informed decisions Regarding the use of this Respiratory personal protective equipment in the face of large-scale outbreaks of Respiratory pathogens.