Tropomi – the most advanced multispectral imaging spectrometer to date – is carried on the Copernicus Sentinel-5P satellite. The instrument was developed jointly by ESA and the Netherlands Space Office. It observes sunlight that is scattered back to space by Earth’s surface and atmosphere, detecting the unique fingerprints of gases in different parts of the spectrum. What sets Tropomi apart is that it measures in the ultraviolet and visible (270–500 nm), near-infrared (675–775 nm) and shortwave infrared (2305–2385 nm) spectral bands. This means that a wide range of pollutants such as nitrogen dioxide, ozone, formaldehyde, sulphur dioxide, methane and carbon monoxide can be imaged more accurately than ever before.