Nitrous Oxide, or laughing gas, is a relative newcomer to the list of industrial pollutants of concern to regulatory bodies monitoring climate change.  It has a stronger greenhouse effect than carbon dioxide and is produced as a by-product of many industrial processes.

The measurement techniques available for this gas are infra-red and electrochemical cell.  Both have their limitations.  The US EPA have produced guidelines on what they consider to be the reference method for measuring N2O as part of the process of legislating for it to be measured and reported by engine and vehicle manufacturers and other industries. They suggest using an infra-red detector that uses a catalyst to oxidise CO, the strongest interferent.