Main-Product

NOx is the collective term for nitrogen oxides, specifically nitric oxide (NO) and nitrogen dioxide (NO₂), which are highly reactive gases composed of nitrogen and oxygen atoms.
These two compounds are the most relevant nitrogen oxides for air pollution

Characteristics

• Nitric oxide (NO) is a colorless, bioactive gas
• Nitrogen dioxide (NO₂) is a reddish-brown, highly toxic gas with a pungent smell

Formation

NO_x primarily forms through combustion processes at high temperatures when nitrogen and oxygen react.
There are three main formation mechanisms:

• Thermal NO_x occurs at temperatures above 1,300°C from nitrogen and oxygen in combustion air.
• Fuel NO_x forms from nitrogen bound in fuel at temperatures from 800°C.
• Prompt NO_x develops under the influence of fuel radicals at the flame front.

During normal combustion, up to 95% of NO_x consists of NO, while NO₂ primarily forms afterward through reaction with atmospheric oxygen.
These compounds play a significant role in the formation of smog and acid rain, as well as affecting tropospheric ozone levels.

Source: Perplexity A.I. search, 1st Jan 2024, Prompt: 'Can you provide a definition of NOx composed of nitrogen and oxygen?'.

Gas