Concept: Non-dispersive infrared spectroscopy (NDIR) in the measurementmethod vocabulary

Concept URI	http://dd.eionet.europa.eu/vocabulary/aq/measurementmethod/NDIR
Preferred label	Non-dispersive infrared spectroscopy (NDIR)
Definition	A nondispersive infrared sensor (or NDIR) sensor is a simple spectroscopic device often used as gas detector. The main components are an infrared source (lamp), a sample chamber or light tube, a wavelength sample chamber, and gas concentration is measured electro-optically by its absorption of a specific wavelength in the infrared (IR). The IR light is directed through the sample chamber towards the detector. In parallel there is another chamber with an enclosed reference gas, typically nitrogen. The detector has an optical filter in front of it that eliminates all light except the wavelength that the selected gas molecules can absorb.
Notation	NDIR
Status	Valid
Status Modified	2013-03-22
Accepted Date	2013-03-22
Not Accepted Date
Scope note	The reference method for the measurement of carbon monoxide is that described in EN 14626:2005 ‘Ambient air quality — Standard method for the measurement of the concentration of carbon monoxide by non-dispersive infrared spectroscopy’