A gas borne substance sampling device (10) includes a housing (12) through which gas can be passed, and a holder (14) for gas borne substance capturing material. The holder (14) is located or locatable inside the housing (12) to contact the capturing material with gas passing through the housing (12). The device (10) has a sampling condition in which at least a major portion of the holder (14) is protected inside or covered by the housing (12) and an analysis condition in which at least a portion of the holder (14) is exposed or outside the housing (12).