Nitric Oxide

Nitric oxide or nitrogen monoxide is a chemical compound with chemical formula NO.
This gas is an important signaling molecule in the body of mammals, including humans, and is an extremely important intermediate in the chemical industry. It is also an air pollutant produced by cigarette smoke, automobile engines and power plants.
Nitric oxide should not be confused with nitrous oxide (N2O), a general anaesthetic and greenhouse gas, or with nitrogen dioxide (NO2), which is another air pollutant. The nitric oxide molecule is a free radical, which is relevant to understanding its high reactivity.
A Nitric Oxide (NO) detector can be used to measure the concentration in the air. There are many gas detectors available, Airmet can help you selecting the correct model for you application. Give us a call or use the product selector below.
Nitric Oxide Characteristics
Synonyms Nitrogen monoxide, Nitrogen oxide
CAS No. 10102-43-9
Chemical formula NO
Vapour density 1.04 (air = 1)
Safe Work Australia ES TWA 25 ppm
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Chemical/physical properties Nitric oxide at room temperature is a colourless, non-flammable gas. It is reported to have a sharp sweet odour usually not detectable by smell below 0.3 to 1 ppm. However, this is probably due to the fact that it readily oxidises in air to nitrogen dioxide and the odour is due to nitrogen dioxide not nitric oxide itself. 
Hazardous properties NO is an important biological molecule, produced naturally by the body and is involved in many physiological processes including that of being a powerful vasodilator (dilates blood vessels, lowers blood pressure and increases blood flow).
If inhaled at high concentrations (e.g. above 25 ppm), NO has a similar effect to carbon monoxide in severely reducing the oxygen carrying capacity of haemoglobin in the blood by combining with it to produce nitrosylhaemoglobin. In this respect it has an even greater affinity to combine with haemoglobin than does carbon monoxide. NO is also reported to have a neurotoxic effect due to its ability to increase blood levels of a substance called methaemoglobin.
Occurrence/Uses NO is formed when nitrogen in the air is oxidised at high temperatures during combustion, electric arc and oxy welding and the detonation of explosives.
NO is also formed in the early stages of the fermentation process in the production of silage. This so called “silo gas” can contain upwards of 140 ppm NO and is a potential hazard on farms where silage is produced.
Due to its vasodilation properties it is used, blended with oxygen, in what is referred to as ‘Nitric Oxide Therapy’ in neonatal intensive care facilities.
Detectors available Electrochemical (0 – 1,000 ppm)
Gas detector tube (10 – 300 ppm)
Suggested alarm levels Lo: 25 ppm
Hi: 30 ppm


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