airpointer®Nitric Oxides (NOx)
The nitric oxide (NO) molecule is very reactive and unstable. In air, it reacts with oxygen to form the poisonous nitrogen dioxide (NO2). Human activity has drastically increased the production of nitric oxide in combustion chambers, e. g. car engines and power plants.Health and Environmental Effects
Nitric oxide has a multitude of effects, primarily in the lung but also in other organs, such as the spleen and the liver. In blood it can lead to the creation of methaemoglobin, which cannot transport oxygen. Nitric oxide in the air may later convert to nitric acid in acid rain. Furthermore, both NO and NO2 participate in the ozone layer reduction.Nitric Oxides and the airpointer®
The concentration of nitric oxides is measured by using chemiluminescence. Nitric oxides in the sample gas react with ozone and this reaction results in electrically excited molecules. These molecules release their excess energy by emitting photons, which are measured by a photomultiplier tube.| Component | EU Directive Method | Principle of Measurement | Range | Units | Lower Detectable Limit | Zero Drift | Span Drift |
| Nitric Oxides (NO/NO2/ NOx) | Chemilumi-nescence (EN 14211) | Chemilumi- nescence |
Dynamic ranges for NO, NO2 and NOx
up to 20 ppm
|
ppm,ppb, μg/m3, mg/m3 | 0.4 ppb | < 0.4 ppb | ±1% of reading or 1 ppb @ <500ppb |