STEL: N/A (Short Term exposure Limit - N/A)
TWA: 100ppm (Time Weighted Average - 8hrs)
Rising Latching Alarms For Line Safety Applications
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Nitric Oxide (NO2)
Nitric oxide (NO2), or nitrogen oxide also known as nitrogen monoxide, is a molecule with the chemical formula NO. At room temperature, Nitric Oxide is a colourless, nonflammable, poisonous, oxidising gas with an irritating odour. NO2 is extremely toxic by inhalation, and symptoms of over-exposure may not become apparent for up to 72 hours. The gas is an oxidiser and will support and enhance combustion. Nitric Oxide fumes may be encountered whenever nitric acid comes in contact with organic material such as wood, sawdust, or refuse. It can also result from heating nitric acid and when organic nitro compounds are burned, for example dynamite. The action of nitric acid upon metals, as in metal etching and pickling, also liberates this dangerous compound.
Nitric Oxide is a free radical and is an important intermediate in the chemical industry. Nitric oxide is a by-product of combustion of substances as in automobile engines, fossil fuel power plants. Although NO2 has relatively few direct uses, it is produced on a massive scale as an intermediate in the Ostwald process for the synthesis of nitric acid from ammonia. In 2005, the US alone produced 6 million metric tons of nitric acid. It finds use in the semiconductor industry for various processes. In one of its applications, it is used along with nitrous oxide to form oxynitride gates in CMOS devices.
Exposure to high concentrations of nitric oxide can cause pulmonary oedema and death. Exposure to low concentrations of fumes, insufficient to cause pulmonary oedema, are said to result in chronic irritation of the respiratory tract, headache, cough, loss of appetite, dyspepsia, corrosion of the teeth and gradual loss of strength.