ISO 21258:2010规定了从管道和烟囱排放到大气中的烟气中一氧化氮（N2O）含量的采样、样品调节和测定方法。介绍了非色散红外（NDIR）分析技术，包括采样系统和样品气体调节系统。 ISO 21258:2010是用于定期监测和校准、调整或控制永久安装在烟囱上的自动监测系统的参考方法。 该参考方法已在污水污泥焚烧炉上成功测试，其中烟气中的N2O浓度高达约200 mg/m3。

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.