Fine dust poses a much greater health risk than nitrogen dioxide.
In view of this
comparatively lower health burden due to nitrogen dioxide, a
Tightening of the applicable limit value not urgent from a scientific point of view.
Source:On the other hand, a further reduction in particulate matter pollution should be sought - including if the less stringent EU limit values for particulate matter are complied with in Germany, and in some cases significantly lower. It has to be taken into account that there are many sources for fine dust.
Ad hoc-statement Clean air
Nitrogen oxides and fine dust in the breathing air:
Basics and recommendations
Leopoldina National Academy of Science