At normal temperatures the oxygen and nitrogen gases do not react together. In the presence of very high temperatures nitrogen and oxygen do react together to form nitric oxide. These conditions are found in the combustion of coal and oil at electric power plants, and also during the combustion of gasoline in automobiles. Both of these sources contribute about equally to the formation of nitrogen oxides.
It’s wild to think that our everyday activities, like driving or using electricity, are contributing to the formation of nitrogen oxides. This makes me wonder about the balance between energy production and air quality. Are there better ways to generate power that reduce these emissions?