Sentinel-5P (TROPOMI)

The Copernicus atmospheric-chemistry precursor mission — a single satellite carrying TROPOMI, the most sensitive spaceborne air-pollution spectrometer flying today. It maps the whole planet’s air quality every single day at unprecedented spatial detail. Not a NASA mission, but NASA’s GES DISC redistributes key products, and the atlas uses it as the backbone of the global air-quality question.

What it sees

• TROPOMI — a hyperspectral spectrometer covering ultraviolet, visible, near-infrared, and shortwave-infrared, measuring how the atmosphere absorbs sunlight to retrieve trace-gas concentrations.
• Pollutants and gases: nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), sulfur dioxide (SO2), formaldehyde (HCHO), methane (CH4), plus aerosol index and cloud properties.
• ~5.5 × 3.5 km pixels — far finer than the earlier OMI sensor, sharp enough to see individual cities, power plants, and shipping lanes.

Why it matters

• Daily, global, high-resolution air quality — you can watch pollution plumes evolve day to day anywhere on Earth, for free.
• The leap in resolution over OMI/Aura makes point-source attribution possible: factories, fires, volcanoes, and traffic corridors stand out.
• A workhorse for methane super-emitter detection and emissions accountability.

Where to get the data

• Copernicus Data Space Ecosystem: dataspace.copernicus.eu — the official ESA archive.
• NASA GES DISC: disc.gsfc.nasa.gov — distributes products such as S5P_L2__NO2___ and the harmonized HAQ TROPOMI NO2, searchable through earthaccess.
• Google Earth Engine: analysis-ready collections for quick mapping.

What it enables

• City- and regional-scale NO2 / air-quality monitoring and trends (air-quality)
• Wildfire and volcanic plume tracking (CO, SO2, aerosol)
• Methane leak and super-emitter detection (atmosphere)
• Ozone and stratospheric chemistry monitoring (atmosphere)
• Public-health and emissions-policy analysis

Gotchas

• Cloud and quality flags are essential. TROPOMI retrievals are degraded under cloud; always apply the qa_value filter (commonly > 0.75 for NO2) before mapping.
• Tropospheric vs total columns. NO2 comes as total and tropospheric columns — pick the one your question needs.
• One satellite, one overpass. Coverage is daily near ~13:30 local time only; no diurnal cycle (that is TEMPO’s job over North America).
• Pixel size has grown finer over the mission — early-archive NO2 used coarser azimuth sampling; account for this in long time series.

Related missions

• TEMPO (NASA): hourly daytime air quality over North America — the diurnal complement to Sentinel-5P’s single daily global snapshot.
• Aura (OMI + MLS) (NASA): TROPOMI’s lower-resolution predecessor; together they extend the air-quality record back to 2004.
• PACE (NASA): aerosol and atmospheric composition from a different vantage.

Related datasets