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