The TROPOMI Aerosol Index (AI), also known as the Ultraviolet Aerosol Index (UVAI), is a well-established data product within the Level-2 processing of S5P/TROPOMI data, with a heritage spanning over 40 years of satellite observations. Its calculation relies on wavelength-dependent changes in Rayleigh scattering within the UV spectral range, where ozone absorption is minimal. Because the AI can be calculated in the presence of clouds, it provides daily, global coverage, making it an ideal tool for tracking the evolution of episodic aerosol plumes from sources such as dust outbreaks, volcanic ash, and biomass burning.

Validation Summary

Dataset Specifications

Examples of filenames (a.k.a. granules):

S5P_OFFL_L2__AER_AI_20260201T231910_20260202T010040_43039_03_020901_20260203T132024.nc S5P_NRTI_L2__AER_AI_20260201T235813_20260202T000313_43039_03_020901_20260202T005247.nc S5P_RPRO_L2__AER_AI_20220701T230527_20220702T004657_24439_03_020400_20230126T042632.nc

Elements in the filename separated by underscores after the initial "S5P":
* processing type: near-real time (NRTI), off-line (OFFL), reprocessing of off-line (RPRO)
* product identifier [10 char.]
* start date and time of granule
* end date and time of granule
* orbit number [5 char.]
* collection number [2 char.]
* version number [6 char.]
* production date and time
In case of OFFL and RPRO granules are full orbits, for NRTI granules are 5-minute chunks of orbits.

Dataset Specifications V2

Temporal Coverage

Since 01-Jul-2021

Reprocessed (RPRO) dataset: from 30-Apr-2018 to 25-Jul-2022

Spatial Coverage

~2600 km swath

Full daily surface coverage of radiance and reflectance measurements for latitudes > 7° and < -7°, and better than 95 % coverage for latitudes in the interval [-7°, 7°]

Spatial Resolution at Nadir

3.5 x 7.0 km (across x along track), at beginning of mission

3.5 x 5.5 km (across x along track), since 6 August 2019

Processor Version02.xx.xx, with x=any digit between 0 and 9

Dataset Specifications V1

Temporal Coverage

From 30-Apr-2018 to 01-Jul-2021

Spatial Coverage

~2600 km swath

Full daily surface coverage of radiance and reflectance measurements for latitudes > 7° and < -7°, and better than 95 % coverage for latitudes in the interval [-7°, 7°]

Spatial Resolution at Nadir

3.5 x 7.0 km (across x along track), at beginning of mission

3.5 x 5.5 km (across x along track), since 6 August 2019

Processor Version01.xx.xx, with x=any digit between 0 and 9

How to Access the Data

The data related to this product and to the other S5P/TROPOMI products are accessible via the  Copernicus Data Space Ecosystem (CDSE).

Documentation and Related Datasets

Technical documentation on the S5P/TROPOMI Level-1B and Level-2 products can be found on the  SentiWiki S5P Products page.

Dataset Citation Guidelines

Users, who, in their research, use ESA Earth Observation data that have been assigned a DOI, are asked to use it when citing the data source in their publications:

Dataset Citation Guidelines V2

Copernicus Sentinel-5P (processed by ESA), 2021, TROPOMI Level 2 Aerosol Index products. Version 02. European Space Agency. https://doi.org/10.5270/S5P-3dgz66p

Dataset Citation Guidelines V1

Copernicus Sentinel-5P (processed by ESA), 2018, TROPOMI Level 2 Aerosol Index products. Version 01. European Space Agency. https://doi.org/10.5270/S5P-0wafvaf