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