Air Quality: Nitrogen Dioxide (NO₂) Satellite Measurements

Average monthly density of nitrogen dioxide (NO₂) in the troposphere


The TROPOMI L3 data are from the Sentinel-5 Precursor (S5p) mission, a low Earth orbit polar satellite system with the objective to provide information and services on air quality, climate and the ozone layer. The S5p mission is part of the Global Monitoring of the Environment and Security (GMES/COPERNICUS) space component program headed by the European Commission (EC) in partnership with the European Space Agency (ESA). The S5p mission includes the TROPOspheric Monitoring Instrument (TROPOMI), which makes daily global observations at a 7 x 3.5 km resolution of key atmospheric constituents. This data layer contains modified Copernicus Sentinel data, in which all data from the most recent 30-day period has been averaged.

The TROPOMI data include satellite measurements for carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), and Absorbing Aerosol Index (AAI).

Nitrogen dioxide (NO₂) is one of a group of highly reactive gases known as oxides of nitrogen or nitrogen oxides (NOx). Other nitrogen oxides include nitrous acid and nitric acid. NO₂ is used as the indicator for the larger group of nitrogen oxides. NO₂ primarily enters the air from the burning of fuel. NO₂ forms from emissions from cars, trucks and buses, power plants, and off-road equipment.

Breathing air with a high concentration of NO₂ can irritate airways in the human respiratory system. Such exposures over short periods can aggravate respiratory diseases, particularly asthma, leading to respiratory symptoms (such as coughing, wheezing or difficulty breathing), hospital admissions and visits to emergency rooms. Longer exposures to elevated concentrations of NO₂ may contribute to the development of asthma and potentially increase susceptibility to respiratory infections. People with asthma, as well as children and the elderly are generally at greater risk for the health effects of NO₂. Resource Watch shows only a subset of the dataset. For access to the full dataset and additional information, see the Learn More link.

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Formal name

Sentinel 5 Precursor Tropospheric Monitoring Instrument (S5P/TROPOMI) Offline (OFFL) Nitrogen Dioxide (NO₂) L3 Monthly Averages


The current surface albedo climatology has a spatial resolution of 0.5° x 0.5°, which is coarse compared to the much higher spatial resolution of S5p TROPOMI of 3.5 x 7 km. As a consequence the albedo grid affects the NO₂ column products quality especially at coastal areas. In general, TROPOMI underestimates the tropospheric NO₂ column at polluted sites. The median negative biases of the daily comparisons are generally less than 50% (the product requirement for tropospheric NO₂) but quite variable depending on station and NO₂ level. Good coherence is found between TROPOMI and Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) NO₂ datasets with a correlation coefficient of 0.84. For a more in depth discussion of bias in different geographic regions, please see the TROPOMI product README files by following the Learn More Link for validation results.

Suggested citation

European Space Agency. 2018. ESA Sentinel-5P TROPOMI L3 products. Accessed through Resource Watch, (date).


Tropospheric Monitoring Instrument (TROPOMI)
European Space Agency (ESA)
Royal Netherlands Meteorological Institute (KNMI)
German Aerospace Center (DLR)
Netherlands Institute for Space Research (SRON)
Belgian Institute for Space Aeronomy (BIRA-IASB)
Science and Technology Facilities Council (STFC)
Max Planck Institute for Chemistry (MPIC)
Science [&] Technology Corporation (S[&]T)
University of Bremen (Uni-Bremen)

Geographic coverage


Spatial resolution

7 x 3.5 km

Date of content


Frequency of updates


Published language



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