A nasal respiratory mask system configured to be placed on a user's face to provide respiratory gas under positive pressure to the user, the nasal respiratory mask system includes: a nasal mask shell configured to cover a user's nose and mouth, the nasal mask shell includes a first valve opening and a second valve opening, wherein the first valve opening is configured to receive a respiratory tube connected to a positive gas pressure source, wherein the second valve opening is configured to enable the entrance of fresh air when the pressure within the nasal mask shell cavity falls below a threshold pressure； and a securing system configured to secure the nasal mask shell to the user's face, wherein the securing system includes at least one horizontal securing strap, wherein the horizontal securing strap extends from a first side face of the nasal mask shell to a second side face of the nasal mask.
