Abstract: An air-discharge device for incorporation in a ceiling comprises an elongate housing of substantially rectangular cross section, such housing having two longitudinal vertical sides, two vertical ends, and a longitudinal upper horizontal side, the longitudinal lower horizontal side being open and substantially flush with the ceiling, each longitudinal vertical side being formed with an elongate lower edge. An air inlet is provided in the housing. Two longitudinal walls extend obliquely into the housing from the respective lower edges of the vertical sides, the inner edges of these two walls defining a longitudinal air passage slot therebetween.