In conjunction with hydrocarbons, nitrogen oxides are responsible for summertime ozone production. Furthermore they contribute to the over-fertilisation and acidification of soils and water bodies. In wintertime, ammonium nitrate particles are formed from nitrogen oxides and contribute to the pollution by particulate matter.
For nitrogen dioxide, an hourly limit value of 200 µg/m3 for protection of human health was established which may not to be exceeded more than 18 times per calendar year. The annual limit value for nitrogen dioxide amounts to 40 µg/m3.