A fold flat personal respiratory device comprising: a generally planar central panel (10) including a layer of filter media and having opposing first and second side edges (12a, 12b) and first and second end edges (11); a first side panel joined to said central panel (10) along said first side edge (12a); a second side panel joined to said central panel (10) along said second side edge (12b); the device being manually configurable from a folded configuration in which said side panels (12a, 12b) are substantially parallel to a planar surface of said central panel (10) and an operational configuration in which said central (10) and first and second side panels (12a, 12b) form a cup-shaped respiratory chamber; the device further comprising a rigid or semi-rigid endoskeleton member (36) mounted along a planar surface of said central panel (10) and extending between said first and second side edges (12a, 12b) and/or said first and second end edges (11).