Nitrous Oxide (N2O) and It's Role in Atmospheric Chemistry

Where N2O comes from ...

Among various other sources, a significant contributor to atmospheric nitrous oxide is soil microbes. Through denitrification (an anaerobic process), nitrate ions (NO3-) are converted into molecular nitrogen 2 gas and nitrous oxide.

Yea ... and?

Nitrous oxide is significant in that it plays a major role in the destruction of stratospheric ozone (the ozone layer) and also contributes to global warming. This remainder of this page will focus on the former.

Nitrous oxide and the ozone layer

Nitrous oxide is a relatively inert gas and thus is able to float through the troposphere without being destroyed by other atmospheric gases. Once the gas reaches the stratosphere, it reacts with excited oxygen (O), a very unstable molecule.

N2O + O (excited) ---> 2NO

Nitric oxide (NO), a chemical known to react with ozone, is produced by this reaction. Nitric oxide then reactions in equilibrium with the available ozone and ozygen:

NO + O3 <---> NO2 + O2

90% of the earth's atmospheric ozone is contained in the stratosphere, which explains why this equilibrium reaction tends towards the destruction of ozone rather than its production. Nitrous oxide is crucial in this decomposition process because nitric oxide by itself will never reach the stratosphere - nitric oxide will react with other tropospheric gases before it reaches the ozone layer.


  • The Ozone Layer
  • Atmospheric Science and the Nobel Prize
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    Jeff R. K. Hartline