Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity? (NEET 2018)

Nitrous oxide (N2O), nitrogen dioxide (NO2) and nitric oxide (NO) are the common pollutants whereas N2O5 is not a common pollutant introduced into the atmosphere. N2O occurs naturally in environment. NO and NO2 causes considerable amount of air pollution. They are given off in car exhaust fumes and when fossil fuels are burnt as well as produced during thunderstorms. In each case, NO is formed first and then NO2.