ALT This image is an artistic preview of what Sentinel-4 might reveal once it becomes operational, drawing on actual NO₂ measurements from the Sentinel-5P satellite. Although Sentinel-4 is still awaiting launch, the vivid colours across Europe in this map illustrate how future instruments will detect and monitor nitrogen dioxide from geostationary orbit, with unprecedented temporal frequency. Captured during a relatively cloud-free winter period, the data will highlight major emission sources—primarily in densely populated or industrial areas—appearing as brighter reds and oranges. These “hotspots” stretch across Central Europe, parts of Italy, and other urbanised regions, underscoring the pervasive impact of human activity on air quality. By comparing the colour-coded concentrations in this artistic impression to actual emission patterns, we gain a glimpse of how Sentinel-4’s future measurements will help track air pollution trends and support policy-making.
