Nitrogen oxide (NO) primarily transforms into nitrogen dioxide (NO2) in the atmosphere through a chemical reaction involving ozone.
The Oxidation Process
According to atmospheric chemistry principles, NO is oxidised by ozone in the atmosphere, on a time scale of tens of minutes, to give NO2. This means that ozone molecules (O3) react with nitrogen oxide molecules (NO), transferring an oxygen atom to NO and forming NO2 and molecular oxygen (O2).
This reaction can be represented simply as:
NO + O3 → NO2 + O2
Atmospheric Context
In rural areas, away from significant sources of NO emissions (like vehicle exhaust or power plants), the majority of atmospheric nitrogen oxides exist as NO2.
It's important to note that NO and NO2 are often grouped together and referred to collectively as NOx. This is because they are rapidly inter-converted during the day through various atmospheric reactions, maintaining a dynamic balance between the two forms. However, the specific process described where NO becomes NO2 through oxidation is a fundamental step in this atmospheric cycle, particularly highlighting the role of ozone.
