An access control system for sensing exposure to items of interest for a person associated with a unique identifier of a fare card or ticket is disclosed. The access control system includes the unique identifier, an exposure detector and a processor. The unique identifier associated with the person that is flagged when exposure is detected. The exposure detector detects exposure to items of interest by the person. The processor is coupled to the exposure detector. The message is communicated away from the processor to a remote location when the unique identifier is flagged.