Method and system for detecting {HEAD ~ one or more gases} or gas mixtures and for measuring {TAIL ~ the concentration} of one or more gases or gas mixtures 
Method and system for detecting { HEAD ~ one or more gases } or gas mixtures and for measuring { TAIL ~ the concentration } of one or more gases or gas mixtures
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH