TEMPO Nitrogen Dioxide (NO2) Tropospheric Vertical Column September 2025-Present (Hourly During Daylight)

Layer Overview The Tropospheric Emissions: Monitoring of Pollution (TEMPO) Nitrogen Dioxide Vertical Column Troposphere layer provides information on the amount of nitrogen dioxide in the troposphere. This is provided as the total number of nitrogen dioxide molecules in the tropospheric column of air above one square centimeter on the Earth’s surface (units: molecules/cm^2). Nitrogen dioxide Level 3 files provide trace gas information on a regular grid. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle, using an area-weighted re-gridding approach. The data have been converted from their native file format (netCDF4) to Cloud Raster Format (CRF). TEMPO V04 algorithms address known issues in the V03, improving data quality. As a result, there are differences between the TEMPO V03 and V04 data. While qualitative analyses and general trends may remain similar between both versions, merging versions for quantitative analysis is discouraged. For details on the changes in the data, please see the User Guide on the TEMPO site.    Note: The information shown here is tropospheric column density (molecules per unit area in the lower atmosphere), not a concentration. Atmospheric concentration refers to the fractional amount of trace gas (e.g., nitrogen dioxide) relative to total air at a specific point, and changes with altitude. Conversion from column density to atmospheric concentration requires additional information, such as the state of the atmosphere and the vertical distribution of the column, which are not provided in this layer. The use of this layer to derive atmospheric concentrations of nitrogen dioxide is discouraged for the non-specialist. Temporal Coverage The temporal resolution of a nominal scan is approximately one hour during daylight hours, with more frequent scans in the morning over the eastern portion of the field of regard and in the evenings over the western portion of the field of regard. Each image is presented with the starting timestamp of the corresponding TEMPO scan. Due to the nature of the TEMPO instrument’s east to west scanning pattern, each image is a composite of measurements taken over a period of 40-60 minutes, depending on the spatial coverage of the scan.    This service was created using TEMPO data version (V03), which was released publicly on May 24, 2024, and cover the time period from August 2, 2023 to September 16, 2025. TEMPO Version 04 (V04) Level 1, 2, and 3 standard data products began production on September 17, 2025. All observations since the beginning of the mission are being reprocessed with V04 algorithms, with V04 products becoming publicly available as they are reprocessed. The TEMPO V04 data are accessible via this service. Once the V03 data reprocessing is completed, this V03 service will be deprecated.   Geographic Coverage Imagery is available for the TEMPO field of regard covering the continental United States (CONUS), much of Mexico, Canada, and the Caribbean. The imagery in this image service is regridded onto a 0.02º longitude x 0.02º latitude grid and presented in the geographic coordinate system WGS 1984. The sensor’s native spatial resolution is ~2 km x 4.75 km at the center of TEMPO’s field of regard (33.5°N, 89.2°W) in WGS 1984. Data Filtering The layer is filtered to remove low-quality pixels using the main data quality flag (removing low confidence measurements), solar zenith angle (removing data retrieved at high solar zenith angles), and effective cloud fraction (removing where clouds obscure the tropospheric column) variables. The filters applied are set to remove pixels based on the following: main_data_quality_flag > 1, eff_cloud_fraction > 0.5, and solar_zenith_angle > 80.  Data Validation These data should be considered as provisional products per the Provisional Product Maturity level defined in the TEMPO validation plan.  These data are at provisional maturity, which means that product performance has been demonstrated through a large, but still (seasonally or otherwise) limited number of independent measurements. The analysis is sufficient for limited qualitative determinations of product fitness-for-purpose, and the product is potentially ready for testing by operational users and may be suitable for scientific publication.  Users may consult the TEMPO User Guide for descriptions of the data and associated known issues.  Recommended Usage Notes When viewing the image service in the Esri online map viewer, it is recommended to use the multidimensional slider rather than the default time slider. The multidimensional slider can be accessed via the “multidimensional” icon in the right-hand menu.  TEMPO Mission Overview The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is a grating spectrometer, sensitive to visible (VIS) and ultraviolet (UV) wavelengths of light with a spectral range of 290-490 + 540-740 nm and 0.6 nm spectral resolution. The TEMPO instrument is attached to the Earth-facing side of a commercial telecommunications satellite (Intelsat 40e) in geostationary orbit over 91˚ W longitude (about 22,000 miles above Earth’s equator). This allows TEMPO to maintain a continuous view of North America so that the instrument's light-collecting mirror can make a complete east-to-west scan of the field of regard hourly during daylight hours. By measuring sunlight reflected and scattered from the Earth's surface and atmosphere back to the instrument's detectors, TEMPO's ultraviolet and visible light sensors provide measurements of ozone, nitrogen dioxide, formaldehyde, and other constituents involved in the chemical dynamics of Earth’s atmosphere. The primary mission objective of TEMPO is to improve our understanding of air quality and its impacts. By providing near real-time data and comprehensive atmospheric composition measurements, TEMPO helps advance knowledge of the Earth system and improve air quality forecasting. These data also aid in quantifying how air quality affects vegetation, agriculture, and human health. Contact For inquiries about this service, please contact larc-dl-asdc-tempo@mail.nasa.gov or post/view questions on the Earthdata Forum.

This item provides the Open Geospatial Consortium (OGC) Web Map Service (WMS) access the TEMPO Nitrogen Dioxide (NO2) Tropospheric Vertical Column service. The source service should be used when access to the actual data is required. The WMS service allows for quick access to the map imagery for consuming and serving dynamic maps.  Layer Overview and Intended Use The Tropospheric Emissions: Monitoring of Pollution (TEMPO) Nitrogen Dioxide Vertical Column Troposphere layer provides information on the amount of nitrogen dioxide in the troposphere. This is provided as the total number of nitrogen dioxide molecules in the tropospheric column of air above one square centimeter on the Earth’s surface (units: molecules/cm^2). Nitrogen dioxide Level 3 files provide trace gas information on a regular grid. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle, using an area-weighted re-gridding approach. The data have been converted from their native file format (netCDF4) to Cloud Raster Format (CRF). Temporal Coverage The temporal resolution of a nominal scan is approximately one hour during daylight hours, with more frequent scans in the morning over the eastern portion of the field of regard and in the evenings over the western portion of the field of regard. Each image is presented with the starting timestamp of the corresponding TEMPO scan. Due to the nature of the TEMPO instrument’s east to west scanning pattern, each image is a composite of measurements taken over a period of 40-60 minutes, depending on the spatial coverage of the scan. Data are updated daily with the previous day's data. Data are available from September 17, 2025 to present and updated daily with the previous day’s data. The previous TEMPO data version (V03) was released publicly on May 24, 2024, and cover the time period from August 2, 2023 to September 16, 2025. All observations since the beginning of the mission are being reprocessed with V04 algorithms, with V04 products becoming publicly available in this service as they are reprocessed. The TEMPO V03 data are accessible via this service. Once the V03 data reprocessing is completed, the V03 service will be deprecated.   Geographic Coverage Imagery is available for the TEMPO field of regard covering the continental United States (CONUS), much of Mexico, Canada, and the Caribbean. The imagery in this image service is regridded onto a 0.02º longitude x 0.02º latitude grid and presented in the geographic coordinate system WGS 1984. The sensor’s native spatial resolution is ~2 km x 4.75 km at the center of TEMPO’s field of regard (33.5°N, 89.2°W) in WGS 1984. Data Filtering The layer is filtered to remove low-quality pixels using the main data quality flag (removing low confidence measurements), solar zenith angle (removing data retrieved at high solar zenith angles), and effective cloud fraction (removing where clouds obscure the tropospheric column) variables. The filters applied are set to remove pixels based on the following: main_data_quality_flag > 1, eff_cloud_fraction > 0.5, or solar_zenith_angle > 80.  Data Validation and Limitations of Use These data should be considered as provisional products per the Provisional Product Maturity level defined in the TEMPO validation plan.  These data are at provisional maturity, which means that product performance has been demonstrated through a large, but still (seasonally or otherwise) limited number of independent measurements. The analysis is sufficient for limited qualitative determinations of product fitness-for-purpose, and the product is potentially ready for testing by operational users and may be suitable for scientific publication.  Users may consult the TEMPO User Guide for descriptions of the data and associated known issues.  TEMPO V04 algorithms address known issues in the V03, improving data quality. As a result, there are differences between the TEMPO V03 and V04 data. While qualitative analyses and general trends may remain similar between both versions, merging versions for quantitative analysis is discouraged. For details on the changes in the data, please see the User Guide on the TEMPO site.  Note: The information shown here is tropospheric column density (molecules per unit area in the lower atmosphere), not a concentration. Atmospheric concentration refers to the fractional amount of trace gas (e.g., nitrogen dioxide) relative to total air at a specific point, and changes with altitude. Conversion from column density to atmospheric concentration requires additional information, such as the state of the atmosphere and the vertical distribution of the column, which are not provided in this layer. The use of this layer to derive atmospheric concentrations of nitrogen dioxide is discouraged for the non-specialist. Recommended Usage Notes When viewing the image service in the Esri online map viewer, it is recommended to use the multidimensional slider rather than the default time slider. The multidimensional slider can be accessed via the “multidimensional” icon in the right-hand menu.  TEMPO Mission Overview The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is a grating spectrometer, sensitive to visible (VIS) and ultraviolet (UV) wavelengths of light with a spectral range of 290-490 + 540-740 nm and 0.6 nm spectral resolution. The TEMPO instrument is attached to the Earth-facing side of a commercial telecommunications satellite (Intelsat 40e) in geostationary orbit over 91˚ W longitude (about 22,000 miles above Earth’s equator). This allows TEMPO to maintain a continuous view of North America so that the instrument's light-collecting mirror can make a complete east-to-west scan of the field of regard hourly during daylight hours. By measuring sunlight reflected and scattered from the Earth's surface and atmosphere back to the instrument's detectors, TEMPO's ultraviolet and visible light sensors provide measurements of ozone, nitrogen dioxide, formaldehyde, and other constituents involved in the chemical dynamics of Earth’s atmosphere. The primary mission objective of TEMPO is to improve our understanding of air quality and its impacts. By providing near real-time data and comprehensive atmospheric composition measurements, TEMPO helps advance knowledge of the Earth system and improve air quality forecasting. These data also aid in quantifying how air quality affects vegetation, agriculture, and human health. Contact For inquiries about this service, please contact larc-dl-asdc-tempo@mail.nasa.gov or post/view questions on the Earthdata Forum.

Layer Overview and Intended UseThe Tropospheric Emissions: Monitoring of Pollution (TEMPO) Nitrogen Dioxide Vertical Column Troposphere Near Real-Time (NRT) layer provides information on the amount of nitrogen dioxide in the troposphere. This is provided as the total number of nitrogen dioxide molecules in the tropospheric column of air above one square centimeter on the Earth’s surface (units: molecules/cm^2). The TEMPO NRT nitrogen dioxide files are produced using a fast version of the TEMPO baseline retrieval processor. TEMPO NRT nitrogen dioxide Level 3 files provide trace gas information on a regular grid. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle, using an area-weighted re-gridding approach. The NRT processing optimizes radiance calibration, image navigation and registration, and cloud and trace gas retrievals for rapid processing, while ensuring that product quality is sufficient for most NRT applications. The data have been converted from their native file format (netCDF4) to Cloud Raster Format (CRF). Temporal CoverageThe temporal resolution of a nominal scan is approximately one hour during daylight hours, with more frequent scans in the morning over the eastern portion of the field of regard and in the evenings over the western portion of the field of regard. Each image is presented with the starting timestamp of the corresponding TEMPO scan. Due to the nature of the TEMPO instrument’s east to west scanning pattern, each image is a composite of measurements taken over a period of 40-60 minutes, depending on the spatial coverage of the scan. Data are updated hourly with any new scans that have been received. Data older than two days (48 hours) are removed from the service. On the rare occasion that the TEMPO instrument is not collecting data for an extended period of time, this service will retain only the latest scan until operations resume. The TEMPO operations log may be found on the TEMPO site.  Geographic CoverageImagery is available for the TEMPO field of regard covering the continental United States (CONUS), and much of Mexico, Canada, and the Caribbean. The imagery in this image service is regridded onto a 0.02º longitude x 0.02º latitude grid and presented in the geographic coordinate system WGS 1984. The sensor’s native spatial resolution is ~2 km x 4.75 km at the center of TEMPO’s field of regard (33.5°N, 89.2°W) in WGS 1984.   Data FilteringThe layer is filtered to remove low-quality pixels using the main data quality flag (removing low confidence measurements), solar zenith angle (removing data retrieved at high solar zenith angles), and effective cloud fraction (removing data where clouds obscure the tropospheric column) variables. The filters applied are set to remove pixels based on the following: main_data_quality_flag > 1, eff_cloud_fraction > 0.5, or solar_zenith_angle > 80.  Data Validation and Limitatations of UseThese data should be considered as provisional products per the Provisional Product Maturity level defined in the TEMPO validation plan. These data are at provisional maturity, which means that product performance has been demonstrated through a large, but still (seasonally or otherwise) limited number of independent measurements. The analysis is sufficient for limited qualitative determinations of product fitness-for-purpose, and the product is potentially ready for testing by operational users and may be suitable for scientific publication. Users may consult the TEMPO User Guide for descriptions of the data and associated known issues.  The information shown here is tropospheric column density (molecules per unit area in the lower atmosphere), not a concentration. Atmospheric concentration refers to the fractional amount of trace gas (e.g., nitrogen dioxide) relative to total air at a specific point, and changes with altitude. Conversion from column density to atmospheric concentration requires additional information, such as the state of the atmosphere and the vertical distribution of the column, which are not provided in this layer. The use of this layer to derive atmospheric concentrations of nitrogen dioxide is discouraged for the non-specialist. Recommended Usage NotesWhen viewing the image service in the Esri online map viewer, it is recommended to use the multidimensional slider rather than the default time slider. The multidimensional slider can be accessed via the “multidimensional” icon in the right-hand menu.  While qualitative analyses and general trends may remain similar between the TEMPO standard and NRT versions, merging versions for quantitative analysis is discouraged. For details on the changes in the data, please see the TEMPO User Guide and the TEMPO NRT Data Products User Guide and ATBD Supplement on the TEMPO site.  The TEMPO NRT ArcGIS service provides access to TEMPO NO2 NRT data earlier than the TEMPO standard NO2 data are available in the standard NO2 ArcGIS service. The TEMPO NRT products are useful for applications with low-latency requirements; however, it is recommended to switch to the TEMPO NO2 Standard Version 04 (V04) service, once the data becomes available in that service. TEMPO V04 data are available from September 17, 2025 to present and the service is updated daily with the previous day’s data. TEMPO Mission OverviewThe Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is a grating spectrometer, sensitive to visible (VIS) and ultraviolet (UV) wavelengths of light with a spectral range of 290-490 + 540-740 nm and 0.6 nm spectral resolution. The TEMPO instrument is attached to the Earth-facing side of a commercial telecommunications satellite (Intelsat 40e) in geostationary orbit over 89˚ W longitude (about 22,000 miles above Earth’s equator). This allows TEMPO to maintain a continuous view of North America so that the instrument's light-collecting mirror can make a complete east-to-west scan of the field of regard hourly during daylight hours. By measuring sunlight reflected and scattered from the Earth's surface and atmosphere back to the instrument's detectors, TEMPO's ultraviolet and visible light sensors provide measurements of ozone, nitrogen dioxide, formaldehyde, and other constituents involved in the chemical dynamics of Earth’s atmosphere. The primary mission objective of TEMPO is to improve our understanding of air quality and its impacts. By providing near real-time data and comprehensive atmospheric composition measurements, TEMPO helps advance knowledge of the Earth system and improve air quality forecasting. These data also aid in quantifying how air quality affects vegetation, agriculture, and human health. ContactFor inquiries about this service, please contact larc-dl-asdc-tempo@mail.nasa.gov or post/view questions on the Earthdata Forum.

This item provides the Open Geospatial Consortium (OGC) Web Map Service (WMS) access the TEMPO Nitrogen Dioxide (NO2) Tropospheric Vertical Column service. The source service should be used when access to the actual data is required. The WMS service allows for quick access to the map imagery for consuming and serving dynamic maps.  Layer Overview The Tropospheric Emissions: Monitoring of Pollution (TEMPO) Nitrogen Dioxide Vertical Column Troposphere layer provides information on the amount of nitrogen dioxide in the troposphere. This is provided as the total number of nitrogen dioxide molecules in the tropospheric column of air above one square centimeter on the Earth’s surface (units: molecules/cm^2). Nitrogen dioxide Level 3 files provide trace gas information on a regular grid. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle, using an area-weighted re-gridding approach. The data have been converted from their native file format (netCDF4) to Cloud Raster Format (CRF). TEMPO V04 algorithms address known issues in the V03, improving data quality. As a result, there are differences between the TEMPO V03 and V04 data. While qualitative analyses and general trends may remain similar between both versions, merging versions for quantitative analysis is discouraged. For details on the changes in the data, please see the User Guide on the TEMPO site.    Note: The information shown here is tropospheric column density (molecules per unit area in the lower atmosphere), not a concentration. Atmospheric concentration refers to the fractional amount of trace gas (e.g., nitrogen dioxide) relative to total air at a specific point, and changes with altitude. Conversion from column density to atmospheric concentration requires additional information, such as the state of the atmosphere and the vertical distribution of the column, which are not provided in this layer. The use of this layer to derive atmospheric concentrations of nitrogen dioxide is discouraged for the non-specialist. Temporal Coverage The temporal resolution of a nominal scan is approximately one hour during daylight hours, with more frequent scans in the morning over the eastern portion of the field of regard and in the evenings over the western portion of the field of regard. Each image is presented with the starting timestamp of the corresponding TEMPO scan. Due to the nature of the TEMPO instrument’s east to west scanning pattern, each image is a composite of measurements taken over a period of 40-60 minutes, depending on the spatial coverage of the scan.    This service was created using TEMPO data version (V03), which was released publicly on May 24, 2024, and cover the time period from August 2, 2023 to September 16, 2025. TEMPO Version 04 (V04) Level 1, 2, and 3 standard data products began production on September 17, 2025. All observations since the beginning of the mission are being reprocessed with V04 algorithms, with V04 products becoming publicly available as they are reprocessed. The TEMPO V04 data are accessible via this service. Once the V03 data reprocessing is completed, this V03 service will be deprecated.   Geographic Coverage Imagery is available for the TEMPO field of regard covering the continental United States (CONUS), much of Mexico, Canada, and the Caribbean. The imagery in this image service is regridded onto a 0.02º longitude x 0.02º latitude grid and presented in the geographic coordinate system WGS 1984. The sensor’s native spatial resolution is ~2 km x 4.75 km at the center of TEMPO’s field of regard (33.5°N, 89.2°W) in WGS 1984. Data Filtering The layer is filtered to remove low-quality pixels using the main data quality flag (removing low confidence measurements), solar zenith angle (removing data retrieved at high solar zenith angles), and effective cloud fraction (removing where clouds obscure the tropospheric column) variables. The filters applied are set to remove pixels based on the following: main_data_quality_flag > 1, eff_cloud_fraction > 0.5, and solar_zenith_angle > 80.  Data Validation These data should be considered as provisional products per the Provisional Product Maturity level defined in the TEMPO validation plan.  These data are at provisional maturity, which means that product performance has been demonstrated through a large, but still (seasonally or otherwise) limited number of independent measurements. The analysis is sufficient for limited qualitative determinations of product fitness-for-purpose, and the product is potentially ready for testing by operational users and may be suitable for scientific publication.  Users may consult the TEMPO User Guide for descriptions of the data and associated known issues.  Recommended Usage Notes When viewing the image service in the Esri online map viewer, it is recommended to use the multidimensional slider rather than the default time slider. The multidimensional slider can be accessed via the “multidimensional” icon in the right-hand menu.  TEMPO Mission Overview The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is a grating spectrometer, sensitive to visible (VIS) and ultraviolet (UV) wavelengths of light with a spectral range of 290-490 + 540-740 nm and 0.6 nm spectral resolution. The TEMPO instrument is attached to the Earth-facing side of a commercial telecommunications satellite (Intelsat 40e) in geostationary orbit over 91˚ W longitude (about 22,000 miles above Earth’s equator). This allows TEMPO to maintain a continuous view of North America so that the instrument's light-collecting mirror can make a complete east-to-west scan of the field of regard hourly during daylight hours. By measuring sunlight reflected and scattered from the Earth's surface and atmosphere back to the instrument's detectors, TEMPO's ultraviolet and visible light sensors provide measurements of ozone, nitrogen dioxide, formaldehyde, and other constituents involved in the chemical dynamics of Earth’s atmosphere. The primary mission objective of TEMPO is to improve our understanding of air quality and its impacts. By providing near real-time data and comprehensive atmospheric composition measurements, TEMPO helps advance knowledge of the Earth system and improve air quality forecasting. These data also aid in quantifying how air quality affects vegetation, agriculture, and human health. Contact For inquiries about this service, please contact larc-dl-asdc-tempo@mail.nasa.gov or post/view questions on the Earthdata Forum.

This item provides the Open Geospatial Consortium (OGC) Web Map Service (WMS) access the TEMPO Nitrogen Dioxide (NO2) Tropospheric Vertical Column Near Real-Time (NRT) service. The source service should be used when access to the actual data is required. The WMS service allows for quick access to the map imagery for consuming and serving dynamic maps.  Layer Overview and Intended UseThe Tropospheric Emissions: Monitoring of Pollution (TEMPO) Nitrogen Dioxide Vertical Column Troposphere Near Real-Time (NRT) layer provides information on the amount of nitrogen dioxide in the troposphere. This is provided as the total number of nitrogen dioxide molecules in the tropospheric column of air above one square centimeter on the Earth’s surface (units: molecules/cm^2). The TEMPO NRT nitrogen dioxide files are produced using a fast version of the TEMPO baseline retrieval processor. TEMPO NRT nitrogen dioxide Level 3 files provide trace gas information on a regular grid. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle, using an area-weighted re-gridding approach. The NRT processing optimizes radiance calibration, image navigation and registration, and cloud and trace gas retrievals for rapid processing, while ensuring that product quality is sufficient for most NRT applications. The data have been converted from their native file format (netCDF4) to Cloud Raster Format (CRF). Temporal CoverageThe temporal resolution of a nominal scan is approximately one hour during daylight hours, with more frequent scans in the morning over the eastern portion of the field of regard and in the evenings over the western portion of the field of regard. Each image is presented with the starting timestamp of the corresponding TEMPO scan. Due to the nature of the TEMPO instrument’s east to west scanning pattern, each image is a composite of measurements taken over a period of 40-60 minutes, depending on the spatial coverage of the scan. Data are updated hourly with any new scans that have been received. Data older than two days (48 hours) are removed from the service. On the rare occasion that the TEMPO instrument is not collecting data for an extended period of time, this service will retain only the latest scan until operations resume. The TEMPO operations log may be found on the TEMPO site.  Geographic CoverageImagery is available for the TEMPO field of regard covering the continental United States (CONUS), and much of Mexico, Canada, and the Caribbean. The imagery in this image service is regridded onto a 0.02º longitude x 0.02º latitude grid and presented in the geographic coordinate system WGS 1984. The sensor’s native spatial resolution is ~2 km x 4.75 km at the center of TEMPO’s field of regard (33.5°N, 89.2°W) in WGS 1984.   Data FilteringThe layer is filtered to remove low-quality pixels using the main data quality flag (removing low confidence measurements), solar zenith angle (removing data retrieved at high solar zenith angles), and effective cloud fraction (removing data where clouds obscure the tropospheric column) variables. The filters applied are set to remove pixels based on the following: main_data_quality_flag > 1, eff_cloud_fraction > 0.5, or solar_zenith_angle > 80.  Data Validation and Limitatations of UseThese data should be considered as provisional products per the Provisional Product Maturity level defined in the TEMPO validation plan. These data are at provisional maturity, which means that product performance has been demonstrated through a large, but still (seasonally or otherwise) limited number of independent measurements. The analysis is sufficient for limited qualitative determinations of product fitness-for-purpose, and the product is potentially ready for testing by operational users and may be suitable for scientific publication. Users may consult the TEMPO User Guide for descriptions of the data and associated known issues.  The information shown here is tropospheric column density (molecules per unit area in the lower atmosphere), not a concentration. Atmospheric concentration refers to the fractional amount of trace gas (e.g., nitrogen dioxide) relative to total air at a specific point, and changes with altitude. Conversion from column density to atmospheric concentration requires additional information, such as the state of the atmosphere and the vertical distribution of the column, which are not provided in this layer. The use of this layer to derive atmospheric concentrations of nitrogen dioxide is discouraged for the non-specialist. Recommended Usage NotesWhen viewing the image service in the Esri online map viewer, it is recommended to use the multidimensional slider rather than the default time slider. The multidimensional slider can be accessed via the “multidimensional” icon in the right-hand menu.  While qualitative analyses and general trends may remain similar between the TEMPO standard and NRT versions, merging versions for quantitative analysis is discouraged. For details on the changes in the data, please see the TEMPO User Guide and the TEMPO NRT Data Products User Guide and ATBD Supplement on the TEMPO site.  The TEMPO NRT ArcGIS service provides access to TEMPO NO2 NRT data earlier than the TEMPO standard NO2 data are available in the standard NO2 ArcGIS service. The TEMPO NRT products are useful for applications with low-latency requirements; however, it is recommended to switch to the TEMPO NO2 Standard Version 04 (V04) service, once the data becomes available in that service. TEMPO V04 data are available from September 17, 2025 to present and the service is updated daily with the previous day’s data. TEMPO Mission OverviewThe Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is a grating spectrometer, sensitive to visible (VIS) and ultraviolet (UV) wavelengths of light with a spectral range of 290-490 + 540-740 nm and 0.6 nm spectral resolution. The TEMPO instrument is attached to the Earth-facing side of a commercial telecommunications satellite (Intelsat 40e) in geostationary orbit over 89˚ W longitude (about 22,000 miles above Earth’s equator). This allows TEMPO to maintain a continuous view of North America so that the instrument's light-collecting mirror can make a complete east-to-west scan of the field of regard hourly during daylight hours. By measuring sunlight reflected and scattered from the Earth's surface and atmosphere back to the instrument's detectors, TEMPO's ultraviolet and visible light sensors provide measurements of ozone, nitrogen dioxide, formaldehyde, and other constituents involved in the chemical dynamics of Earth’s atmosphere. The primary mission objective of TEMPO is to improve our understanding of air quality and its impacts. By providing near real-time data and comprehensive atmospheric composition measurements, TEMPO helps advance knowledge of the Earth system and improve air quality forecasting. These data also aid in quantifying how air quality affects vegetation, agriculture, and human health. ContactFor inquiries about this service, please contact larc-dl-asdc-tempo@mail.nasa.gov or post/view questions on the Earthdata Forum.

Ozone Overview and Intended Use Ozone (O₃) is a gas composed of three oxygen atoms and is naturally present in our atmosphere. It has a profound influence on life on Earth and the atmosphere. It exists in different layers of the atmosphere, with the largest abundance in the stratosphere, where it forms the ozone layer. This layer absorbs harmful ultraviolet (UV) radiation from the Sun, preventing it from reaching the surface and reducing the risk of skin cancer, cataracts, and other health issues, while also protecting ecosystems. However, ozone near the ground is a major pollutant that can cause respiratory problems and environmental damage. In addition, ozone plays a critical role in the oxidizing capacity of the troposphere and acts as an important greenhouse gas in the upper troposphere and lower stratosphere. Therefore, we monitor total column ozone and its vertical distribution using various instruments such as satellites and ground-based observations.   These observations usually provide the ozone columns as Dobson Units (DU), which is a unit of measurement of the amount of a trace gas in a vertical column through the Earth’s atmosphere. Per the definition of Dobson units, 1 Dobson Unit corresponds to a 0.01 mm thick ozone layer at standard atmospheric conditions (0°C (or 273.15 K), 1 atm (or 1013.25 hPa)). Understanding and tracking ozone levels is crucial for assessing environmental changes, monitoring ozone depletion, and ensuring the continued protection of life on Earth.   Layer Overview The Tropospheric Emissions: Monitoring of Pollution (TEMPO) Gridded Total Column Ozone layer provides information on the amount of ozone in the atmosphere as a total column, expressed in Dobson Units (DU). In other words, it represents the total amount of ozone molecules present in the atmosphere from the Earth’s surface to the top of the atmosphere. Ozone Level 3 files provide trace gas information on a regular grid consisting of 0.02° x 0.02° grid points across the field of regard. Level 3 files are derived by combining information from all Level 2 files constituting a TEMPO East-West scan cycle, using an area-weighted re-gridding approach. The data have been converted from their native file format (netCDF4) to Cloud Raster Format (CRF).   Temporal Coverage The temporal resolution of a nominal scan is approximately one hour during daylight hours, with more frequent scans in the morning over the eastern portion of the field of regard and in the evenings over the western portion of the field of regard. Each image is presented with the starting timestamp of the corresponding TEMPO scan. Due to the nature of the TEMPO instrument’s east to west scanning pattern, each image is a composite of measurements taken over a period of 40-60 minutes, depending on the spatial coverage of the scan. Data are available from September 17, 2025 to present and updated daily with the previous day’s data.   The previous TEMPO data version (V03) was released publicly on May 24, 2024, and cover the time period from August 2, 2023 to September 16, 2025. All observations since the beginning of the mission are being reprocessed with V04 algorithms, with V04 products becoming publicly available in this service as they are reprocessed. The TEMPO V03 data are accessible via this service. Once the V03 data reprocessing is completed, the V03 service will be deprecated.     Geographic Coverage Imagery is available for the TEMPO field of regard covering the continental United States (CONUS), much of Mexico, Canada, and the Caribbean. The imagery in this image service is regridded onto a 0.02º longitude x 0.02º latitude grid and presented in the geographic coordinate system WGS 1984. The sensor’s native spatial resolution is ~2 km x 4.75 km at the center of TEMPO’s field of regard (33.5°N, 89.2°W) in WGS 1984.   Data Filtering The layer is filtered to remove low-quality pixels based using the solar zenith angle (removing data retrieved at high solar zenith angles) and viewing zenith angle (removing data retrieved at high viewing zenith angles). The applied filters remove pixels based on the following: solar_zenith_angle > 80 or viewing_zenith_angle > 80. The filtering using the quality flag is pre-applied during the Level 3 data generation process to remove pixels based on quality_flag is not 0, 1, 2, or 5.   Data Validation and Limitations of Use These data should be considered as provisional products per the Provisional Product Maturity level defined in the TEMPO validation plan. These data are at provisional maturity, which means that product performance has been demonstrated through a large, but still (seasonally or otherwise) limited number of independent measurements. The analysis is sufficient for limited qualitative determinations of product fitness-for-purpose, and the product is potentially ready for testing by operational users and may be suitable for scientific publication. Users may consult the user guide for descriptions of the data and associated known issues.  TEMPO V04 algorithms address known issues in the V03, improving data quality. As a result, there are differences between the TEMPO V03 and V04 data. While qualitative analyses and general trends may remain similar between both versions, merging versions for quantitative analysis is discouraged. For details on the changes in the data, please see the User Guide on the TEMPO site.  Recommended Usage Notes When viewing the image service in the ESRI online map viewer, it is recommended to use the multidimensional slider rather than the default time slider. The multidimensional slider can be accessed via the “multidimensional” icon in the right-hand menu.  TEMPO Mission Overview  The TEMPO instrument is a grating spectrometer, sensitive to visible (VIS) and ultraviolet (UV) wavelengths of light with a spectral range of 290-490 + 540-740 nm and 0.6 nm spectral resolution. The TEMPO instrument is attached to the Earth-facing side of a commercial telecommunications satellite (Intelsat 40e) in geostationary orbit over 91˚ W longitude (about 22,000 miles above Earth’s equator). This allows TEMPO to maintain a continuous view of North America so that the instrument's light-collecting mirror can make a complete east-to-west scan of the field of regard hourly during daylight hours. By measuring sunlight reflected and scattered from the Earth's surface and atmosphere back to the instrument's detectors, TEMPO's UV and VIS light sensors provide measurements of ozone, nitrogen dioxide, formaldehyde, and other constituents involved in the chemical dynamics of Earth’s atmosphere.   The primary mission objective of TEMPO is to improve our understanding of air quality and its impacts. By providing near real-time data and comprehensive atmospheric composition measurements, TEMPO helps advance knowledge of the Earth system and improve air quality forecasting. These data also aid in quantifying how air quality affects vegetation, agriculture, and human health.   Contact For inquiries about this service, please contact larc-dl-asdc-tempo@mail.nasa.gov or post/view questions on the  Earthdata Forum.