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