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.