NOx

NO_x is a generic term for the mono-nitrogen oxides NO and NO₂ (nitric oxide and nitrogen dioxide). They are produced from the reaction among nitrogen, oxygen and even hydrocarbons (during combustion), especially at high temperatures. In areas of high motor vehicle traffic, such as in large cities, the amount of nitrogen oxides emitted into the atmosphere as air pollution can be significant. NO_x gases are formed whenever combustion occurs in the presence of nitrogen – as in an air-breathing engine; they also are produced naturally by lightning. In atmospheric chemistry, the term means the total concentration of NO and NO₂. NO_x gases react to form smog and acid rain as well as being central to the formation of tropospheric ozone.

Nox may refer to:

• NO_x, a generic term for the mono-nitrogen oxides:
  • Nitric oxide (NO)
  • Nitrogen dioxide  (NO₂)
• Nox (unit) (nx), a unit of illuminance
• Nox (platform), a piece of the software-defined networking ecosystem