Hygiene mask with seal forming structure

A mask for use at an operating pressure substantially equal to atmospheric pressure, the mask comprising:

• a body forming a three-dimensional shaped chamber configured to operate at the operating pressure throughout a user's respiratory cycle and configured to receive the user's mouth and nares, wherein an inner surface of the body is configured to be spaced apart from the user in use throughout the user's respiratory cycle;
• and
• a nose portion having a surface defining a plane at its most superior side that is configured and sized to avoid contact with and intersection of the user's nasal ridge, the surface on the most superior side of the nose portion being configured to contact the user's nose along the user's sagittal plane and around at least a portion of the user's nares on an inferior side of the user's nose inferior to the user's nasal ridge without intersecting the user's sagittal plane at the user's lip superior and without entering the user's nasal passages, at least a portion of the nose portion is configured to direct airflow through the user's nose and is configured to limit airflow toward the user's eyes in use;
• and
• a positioning and stabilising structure to provide a force to hold the nose portion in position on the user's head;
• wherein at least a portion of the body is configured to allow passage of air into and out of the three-dimensional shaped chamber.