Presently,　numerous　state-of-the-art　approaches　are　being　adapted　for　gas　sensing　and　monitoring.　These　include　hazardous　gas　leak　detection　as　well　as　ambient　air　monitoring.　Photoionization　detectors,　electrochemical　sensors,　and　optical　infrared　sensors　are　a　few　of　the　commonly　widely　used　technologies.　Extensive　reviews　on　the　current　state　of　gas　sensors　have　been　summarized.　These　sensors,　which　are　either　nonselective　or　semiselective,　are　affected　by　unwanted　analytes.　On　the　other　hand,　volatile　organic　compounds　(VOCs)　can　be　heavily　mixed　in　many　vapor　intrusion　situations.　To　determine　the　individual　VOCs　in　a　highly　mixed　gas　sample　using　nonselective　or　semiselective　gas　sensors,　gas　separation　and　discrimination　technologies　are　highly　warranted.　These　technologies　include　gas　permeable　membranes,　metal-organic　frameworks,　microfluidics　and　IR　bandpass　filters　for　different　sensors,　respectively.　The　majority　of　these　gas　separation　and　discrimination　technologies　are　currently　being　developed　and　evaluated　in　laboratory-controlled　environments　and　have　not　yet　been　extensively　utilized　in　the　field　for　vapor　intrusion　monitoring.　These　technologies　show　promise　for　continued　development　and　application　in　the　field　for　more　complex　gas　mixtures.　Hence,　the　present　review　focuses　on　the　perspectives　and　a　summary　of　the　existing　gas　separation　and　discrimination　technologies　for　the　currently　popular　reported　gas　sensors　in　environmental　applications.