Nitrogen dioxide over the Netherlands on 20 March 2025: dark red from The Hague to beyond Amsterdam, measured by Sentinel-5P

The amount of nitrogen dioxide (NO₂) in the air column above the ground, measured by the TROPOMI instrument on Sentinel-5P during its overpass around midday. According to the legend, the colour runs from light yellow (almost nothing) through orange to dark red (2 × 10¹⁶ molecules per cm² or more). The dark red lies in a band from The Hague via Leiden to beyond Amsterdam; a second dark patch lies between Antwerp and Bergen op Zoom, and at the bottom right the Ruhr area shows red. It is a column, not the air you breathe at street level, and every day the picture looks different.