ISO International Standard

ISO 21258:2010 specifies a method for sampling, sample conditioning and determination of dinitrogen monoxide (N₂O) content in the flue gas emitted from ducts and stacks to atmosphere. It sets out the non-dispersive infrared (NDIR) analytical technique, including the sampling system and sample gas conditioning system.

ISO 21258:2010 is a reference method for periodic monitoring and for calibration, adjustment or control of automatic monitoring systems permanently installed on a stack.

This reference method has been successfully tested on a sewage sludge incinerator where the N₂O concentration in the flue gas was up to about 200 mg/m³.