A device for detection of substances transmitted into the body surrounding environment through body boundaries including a first sensor arranged to face a body boundary surface and structured to locally detect a substance indicative of at least one targeted substance of interest transmitted through the body boundary surface in proximity of the body boundary surface of a monitored subject. The device also includes a second sensor arranged to face in an opposite direction from the body boundary surface and structured to detect in a surrounding environment at least one substance indicative of the targeted substance of interest transmitted through the body boundary surface of the monitored subject. In addition the device further include an electronic circuit structured to receive and process the signals generated by the first and second sensors, and to determine presence of the at least one targeted substance of interest.
