Nitrogen oxides, primarily nitric oxide (NO) and nitrogen dioxide (NO2), are gases produced during combustion processes at high temperatures.

Sources:

  • Vehicle emissions.
  • Power plants and industrial boilers.
  • Agricultural activities and fertilizer use.

Effects:

  • Environmental: Contributes to the formation of smog and acid rain, and leads to the formation of ground-level ozone.
  • Health: Causes respiratory problems, aggravates asthma, and reduces lung function.

Measurement:

  • Chemiluminescence Gas Analyzers: Measure NOx concentration based on the light emitted during a chemical reaction.
  • Electrochemical Sensors: Detect NO and NO2 concentrations using chemical reactions producing electrical signals.