Face mask for deflecting respiratory aerosols generated by the wearer

Abstract

A facemask to be worn in an enclosed space by a subject having or suspected of having a disease transmitted in exhaled aerosol particles is provided. The facemask comprises an air-permeable body having an outer surface facing away from the face of the subject, an inner surface facing toward the face, an upper edge cephalad, a lower edge caudad, and lateral edges at each side of the face such that the inner surface covers the subject's nose and mouth and is spaced apart therefrom. Moreover, at least a portion of the upper and lower edges is spaced apart from the face, but the lateral edges are not spaced apart. The upward and downward deflection of aerosol plumes exiting the facemask cooperates with airflow in the enclosed space to reduce exposure of occupants of the space to the subject's exhaled aerosol particles.

I claim: 
     
         1 . A facemask configured to be worn by a subject, said facemask comprising an air-permeable body having, when worn, an outer surface facing away from the face of said subject, an inner surface facing toward said face, an upper edge cephalad, a lower edge caudad, and lateral edges at each side of said face such that:
 a) said inner surface covers said nose and mouth and is spaced apart therefrom so as to create a plenum defined by said upper, lower and lateral edges and having only first and second openings;   b) at least a portion of said upper edge is spaced apart from said face so as to define said first opening;   c) at least a portion of said lower edge is spaced apart from said face so as to define said second opening, and   d) said lateral edges are not spaced apart from said face and contact the cheeks of said face.   
     
     
         2 . The facemask of  claim 1 , wherein said plenum extends cephalad to said first opening. 
     
     
         3 . The facemask of  claim 1 , wherein said plenum extends caudad to said second opening. 
     
     
         4 . The facemask of  claim 1 , wherein said body comprises a rigid material. 
     
     
         5 . The facemask of  claim 1 , wherein said body comprises a flexible material. 
     
     
         6 . The facemask of  claim 5 , wherein said flexible material is elastic. 
     
     
         7 . The facemask of  claim 1 , wherein said body comprises a first portion comprising an air-impermeable material and a second portion comprising an air-permeable material. 
     
     
         8 . A system comprising:
 a) a facemask according to  claim 1 , and   b) an enclosure comprising a floor, a ceiling and a wall therebetween, wherein said floor, ceiling and wall define an enclosed space, and wherein said enclosed space contains an ambient, breathable gas.   
     
     
         9 . The system of  claim 9 , wherein said enclosed space comprises an overhead space, a mid-level space disposed below said overhead space, and a lower-level space disposed below said mid-level space, wherein said overhead and mid-level spaces are contiguous and in fluid communication and wherein said mid-level and lower-level spaces are contiguous and in fluid communication. 
     
     
         10 . The system of  claim 9 , wherein said enclosure is ventilated. 
     
     
         11 . The system of  claim 10 , wherein said ceiling, wall or floor is fenestrated. 
     
     
         12 . The system of  claim 10 , wherein said enclosure is ventilated at a rate of at least five enclosure volume exchanges per hour. 
     
     
         13 . The system of  claim 10 , wherein said enclosure is ventilated by an air handler. 
     
     
         14 . A method of positioning a facemask on a human subject, comprising a) providing a facemask comprising an air-permeable body having an outer surface, an inner surface, an upper edge, a lower edge and lateral edges; and b) positioning said facemask on the face of said human subject such that said outer surface faces away from the face of said subject, said inner surface faces toward said face, said upper edge is positioned cephalad, said lower edge is positioned caudad, and said lateral edges contact each side of said face such that:
 i) said inner surface covers the human subject's nose and mouth and is spaced apart therefrom so as to create a plenum defined by said upper, lower and lateral edges and having only first and second openings;   ii) at least a portion of said upper edge is spaced apart from said face so as to define said first opening;   v) at least a portion of said lower edge is spaced apart from said face so as to define said second opening, and   vi) said lateral edges are not spaced apart from said face and are in contact with the cheeks of said face.   
     
     
         15 . A method of reducing an accumulation of aerosol particles in at least a mid-level space of a ventilated enclosure consequent to an aerosol plume created by a subject in said enclosure, the method comprising:
 a) providing
 i) said subject; 
 ii) said ventilated enclosure; 
 iii) a facemask according to  claim 1 , 
 iv) a pre-determined standard accumulation of said airborne aerosol particles in said mid-level space; 
   b) positioning said facemask according to the method of  claim 14  on said face over said nose and mouth to create a positioned mask, and   c) causing said subject to create an aerosol plume, such that said accumulation is less than said standard accumulation.   
     
     
         16 . The method of claim  29 , wherein said subject has, or is suspected of having, a disease spread by airborne aerosol particles.