Gaseous constituent supply device for vehicle

A gaseous constituent supply device for supplying an air cannon projectile containing a predetermined gaseous constituent to an occupant in a compartment of a vehicle, comprising:

• a humidity constituent generating unit for generating a humidity constituent to be contained in the air cannon projectile;
• a gaseous constituent chamber for reserving the gaseous constituent;
• air compression means for compressing an inside of the gaseous constituent chamber to generate an air cannon projectile including the humidity constituent;
• a humidity sensor for detecting a humidity of air in the compartment;
• and
• a control unit which controls the humidity constituent generating unit and the compression means so that an air cannon projectile including a predetermined amount of the humidity constituent is emitted to the occupant when the humidity of air detected by the humidity sensor is lower than a predetermined value.