A vapor sensor comprises a housing with an inlet opening in fluid communication with a sensor element within the housing. Standoff member(s) are positioned to maintain a gap between the inlet opening and a skin site. An operating circuit is in electrical communication with the sensor element and communicatively coupled to an output member. In use, the output member generates a sensory output indicative to an operator regarding concentration of alcoholic vapor in the ambient atmosphere proximate the skin site upon receiving communication from the operating circuit.