Nitrogen oxides (NOx) emissions in Spain 1990-2021
Emissions of nitrogen oxides in Spain were 621,000 metric tons in 2021. Although this was an increase from the previous year, NOx emissions in Spain have experienced an overall reduction of 53 percent since 1990.
Nitrogen oxides (NOx) mainly include nitric oxide (NO) and nitrogen dioxide (NO₂), which contribute to the formation of smog and acid rain. The main source of NOx in Spain is road transportation.