{HEAD ~ Nitrogen dioxide gas} is sensed in {TAIL ~ accordance} with a color change before and after the sensor element is exposed to air to be measured for a predetermined time 
is sensed in
{ HEAD ~ Nitrogen dioxide gas } is sensed in { TAIL ~ accordance } with a color change before and after the sensor element is exposed to air to be measured for a predetermined time
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH