ProductsApplication
Nitrogen dioxideozoneSulfure dioxideAmmoniaBenzeneHydrogen Sulfide
Long Term   |  Short Term |  NOx
 
Nitrogen Oxides NOx
Diagram
Specifications
Fullversion
t

NOx direct measurement of NO2 equivalent
NOx indirect measurement via NO

The sampler is based on that of Palmes. The absorbing medium contains the oxidant PTIO, which transforms NO to NO2.
NOx is expressed in Nitrite equivalents.

The measurement of NOx is carried out with two different samplers: firstly NO2 is assessed with Triethanolamin and
secondly NO + NO2 is trapped after transforming NO into NO2 with an oxidizing agent in the TEA

The samplers are placed in a special shelter and equipped with membranes to measure near spots with high traffic.

Diagram


  
Figure left: NOx assessed as NO2 equivalents using NOx sampler only

Figure right: NOx assessed as difference of total NOx and NO2 using NOx and NO2 sampler simultaneously the coincidence with NOx Monitor is remarkably better in the latter case.

Specifications

Sampling Rate NO2
Sampling Rate NO

0.827 ml/min at  20oC     with membrane
1.069 ml/min at  20oC     with membrane

Working range

1 — 200 µg/m3

Sampling time

2 — 4 weeks

Detection limit

0.2 µg/m3 for a sampling time of 14 days

External influences:
   wind speed
 influence of wind speed < 10% up to 6.0 m/sec
using membranes
   temperature
 no information
   humidity
 ± 10 %  between 20 to 80%

Storage

before use:                      6 months  at 4oC
after exposure:                6 months  at 4oC

Cross sensitivity

Selective method

Expanded uncertainty*

33.7 % at concentration levels of 1 - 30 µg/m3

*according to GUM;
subject to change without notice
revised 3.1.2010

 
 
2009 Copyright  by passam ag