TEMPO surface PM2.5 concentrations showing the impact of Sandy Fire (Average throughout May 18) for the California Wildfires May 2026

Dates of Images: May 18- 25, 2026 Summary This product provides the PM2.5 impacts at the surface from the Sandy Fire by calculating the total number of daytime hours when surface fine particulate matter (PM2.5) exceeded the 35 µg/m³ health threshold for sensitive groups (USG). Surface concentrations of PM2.5 Level 4 (L4) files were generated from Tropospheric Emissions: Monitoring of Pollution (TEMPO) Satellite and Advanced Baseline Imager (ABI) aerosol retrievals. The aerosol optical depth (AOD) and PM2.5 products were created at NOAA/NESDIS. The data covers the daytime observation windows during the active fire period from May 18 to May 25, 2026. Because TEMPO relies on sunlight, these observations represent approximately 10 to 12 hours of sun-lit coverage per calendar day rather than a full 24-hour cycle. For emergency managers, this highlights total cumulative exposure durations, allowing officials to efficiently target health impacts in heavily affected communities. Caveats and Limitations Since the TEMPO instrument only makes observations during daylight hours, communities likely experienced significant additional nighttime smoke exposure that is not captured in these products. Furthermore, dense cloud cover can block satellite measurements, and these values may underestimate the true duration of smoke exposure in persistently cloudy areas. TEMPO data also exhibits more noise at the edges of clouds. Suggested Use While hours when surface PM2.5 was greater than 35 µg/m³ represents the health standard referred to as "Unhealthy for Sensitive Groups," this daytime-only product is developed only for rapid disaster response and should not be used for official EPA regulatory compliance, which requires a full 24-hour average. Red colors in the image represent more hours when the surface pM2.5 concentrations were higher than 35 µg/m³. Satellite/Sensor/Resolution The surface PM2.5 product is estimated using data from two primary instruments: the TEMPO spectrometer aboard the Intelsat-40e commercial satellite and the Advanced Baseline Imager (ABI) on the GOES-R Series satellites (GOES-East and GOES-West). The final product is derived using a geographically weighted regression (GWR) algorithm that combines satellite aerosol optical depth (AOD) and aerosol layer height (ALH) with hourly data from AIRNOW surface monitors. While the raw TEMPO data has a native resolution of 2.0 km by 4.75 km, it is re-scaled to match the ABI's fixed grid, resulting in a final product with a spatial resolution of 2 km. Credits AOD and PM2.5 were provided by NOAA/NESDIS. Data analysis and cumulative exposure maps were created by Dr. Aishwarya Raman (BAERI/NASA ARC). Point of contact for TEMPO PM2.5 data - Amy Huff (Science and Technology Corporation (STC) at NOAA) and Shobha Kondragunta (NOAA). Esri REST Endpoint: See URL to the right. Data Download For data, please contact Amy Huff (Science and Technology Corporation (STC) at NOAA) and Shobha Kondragunta (NOAA).

Dates of Images: May 18- 25, 2026 Summary This product provides the PM2.5 impacts on air at the surface from the Sandy Fire by calculating the total number of daytime hours when surface-air fine particulate matter (PM2.5) exceeded the 35 µg/m³ health threshold for sensitive groups (USG). Surface concentrations of PM2.5 Level 4 (L4) files were generated from Tropospheric Emissions: Monitoring of Pollution (TEMPO) Satellite and Advanced Baseline Imager (ABI) aerosol retrievals. The aerosol optical depth (AOD), an intermediate data product input for this analysis, and PM2.5 products were created at NOAA/NESDIS. The data covers the daytime observation windows during the active fire period from May 18 to May 25, 2026. Because TEMPO relies on sunlight, these observations represent approximately 10 to 12 hours of sun-lit coverage per calendar day rather than a full 24-hour cycle. For emergency managers, this highlights total cumulative exposure durations, allowing officials to efficiently target health impacts in heavily affected communities. Caveats and Limitations Since the TEMPO instrument only makes observations during daylight hours, communities likely experienced significant additional nighttime smoke exposure that is not captured in these products. Furthermore, dense cloud cover can block satellite measurements, and these values may underestimate the true duration of smoke exposure in persistently cloudy areas. TEMPO data also exhibits more noise at the edges of clouds. Suggested Use While hours when surface PM2.5 was greater than 35 µg/m³ represents the health standard referred to as "Unhealthy for Sensitive Groups," this daytime-only product is developed only for rapid disaster response and should not be used for official EPA regulatory compliance, which requires a full 24-hour average. Red colors in the image represent more hours when the surface pM2.5 concentrations were higher than 35 µg/m³. Satellite/Sensor/Resolution The estimated surface PM2.5 product is generated using data from two primary instruments: the TEMPO spectrometer aboard the Intelsat-40e commercial satellite and the Advanced Baseline Imager (ABI) on the GOES-R Series satellites (GOES-East and GOES-West). The final product is derived using a geographically weighted regression (GWR) algorithm that combines satellite aerosol optical depth (AOD) and aerosol layer height (ALH) with hourly data from AIRNOW surface monitors. While the raw TEMPO data has a native resolution of 2.0 km by 4.75 km, it is re-scaled to match the ABI's fixed grid, resulting in a final product with a spatial resolution of 2 km. Credits AOD and PM2.5 was provided by NOAA/NESDIS. Data analysis and cumulative exposure maps were created by Dr. Aishwarya Raman (BAERI/NASA ARC). Point of contact for TEMPO PM2.5 data - Amy Huff (Science and Technology Corporation (STC) at NOAA) and Shobha Kondragunta (NOAA). Data Download For data, please contact Amy Huff (Science and Technology Corporation (STC) at NOAA) and Shobha Kondragunta (NOAA).

Dates of Images: July 4-July 8 Summary: This product provides the PM2.5 impacts at the surface from the Sandy Fire by calculating the total number of daytime hours when surface fine particulate matter (PM2.5) exceeded the 35 µg/m³ health threshold for sensitive groups (USG). Surface concentrations of PM2.5 Level 4 (L4) files were generated from Tropospheric Emissions: Monitoring of Pollution (TEMPO) Satellite and Advanced Baseline Imager (ABI) aerosol retrievals. The aerosol optical depth (AOD) and PM2.5 products were created at NOAA/NESDIS. The data covers the daytime observation windows during the active fire period from May 18 to May 25, 2026. Because TEMPO relies on sunlight, these observations represent approximately 10 to 12 hours of sun-lit coverage per calendar day rather than a full 24-hour cycle. For emergency managers, this highlights total cumulative exposure durations, allowing officials to efficiently target health impacts in heavily affected communities. Caveats and Limitations: Since the TEMPO instrument only makes observations during daylight hours, communities likely experienced significant additional nighttime smoke exposure that is not captured in these products. Furthermore, dense cloud cover can block satellite measurements, and these values may underestimate the true duration of smoke exposure in persistently cloudy areas. TEMPO data also exhibits more noise at the edges of clouds. Suggested Use: While hours when surface PM2.5 was greater than 35 µg/m³ represents the health standard referred to as "Unhealthy for Sensitive Groups," this daytime-only product is developed only for rapid disaster response and should not be used for official EPA regulatory compliance, which requires a full 24-hour average. Red colors in the image represent more hours when the surface pM2.5 concentrations were higher than 35 µg/m³. Satellite/Sensor/Resolution: The surface PM2.5 product is estimated using data from two primary instruments: the TEMPO spectrometer aboard the Intelsat-40e commercial satellite and the Advanced Baseline Imager (ABI) on the GOES-R Series satellites (GOES-East and GOES-West). The final product is derived using a geographically weighted regression (GWR) algorithm that combines satellite aerosol optical depth (AOD) and aerosol layer height (ALH) with hourly data from AIRNOW surface monitors. While the raw TEMPO data has a native resolution of 2.0 km by 4.75 km, it is re-scaled to match the ABI's fixed grid, resulting in a final product with a spatial resolution of 2 km. Credits: AOD and PM2.5 were provided by NOAA/NESDIS. Data analysis and cumulative exposure maps were created by Dr. Aishwarya Raman (BAERI/NASA ARC). Point of contact for TEMPO PM2.5 data - Amy Huff (Science and Technology Corporation (STC) at NOAA) and Shobha Kondragunta (NOAA). Esri REST Endpoint: See URL to the right. Data Download: For data, please contact Amy Huff (Science and Technology Corporation (STC) at NOAA) and Shobha Kondragunta (NOAA).

Abstract and Limitations of Use: The Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD), 1998-2019, V4.GL.03 consists of annual concentrations (micrograms per cubic meter) of all composition ground-level fine particulate matter (PM2.5). This data set combines AOD retrievals from multiple satellite algorithms including the NASA MODerate resolution Imaging Spectroradiometer Collection 6.1 (MODIS C6.1), Multi-angle Imaging SpectroRadiometer Version 23 (MISRv23), MODIS Multi-Angle Implementation of Atmospheric Correction Collection 6 (MAIAC C6), and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) Deep Blue Version 4. The GEOS-Chem chemical transport model is used to relate this total column measure of aerosol to near-surface PM2.5 concentration. Geographically Weighted Regression (GWR) is used with global ground-based measurements from the World Health Organization (WHO) database to predict and adjust for the residual PM2.5 bias per grid cell in the initial satellite-derived values. These estimates are primarily intended to aid in large-scale studies. Gridded data sets are provided at a resolution of 0.01 degrees to allow users to agglomerate data as best meets their particular needs. Data sets are gridded at the finest resolution of the information sources that were incorporated, but do not fully resolve PM2.5 gradients at the gridded resolution due to influence by information sources at coarser resolution. The data are distributed as GeoTIFF files and are in WGS84 projection. Because this is a historical dataset, this item does not follow a routine update frequency.   Intended Use: To provide an annual global surface of concentrations (micrograms per cubic meter) of all composition ground-level fine particulate matter of 2.5 micrometers or smaller (PM2.5) for large-scale health and environmental research. Legend:ColorLegend LabelDescription: 80 - 139Annual concentrations (micrograms per cubic meter) of all composition ground-level fine particulate matter (PM2.5) 40 - 80 20 - 40 10 - 20 5 - 10 0 - 5Citation: Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD), 1998-2019, V4.GL.03. Hammer, M. S., A. van Donkelaar, C. Li, A. Lyapustin, A. M. Sayer, N. C. Hsu, R. C. Levy, M. J. Garay, O. V. Kalashnikova, R. A. Kahn, M. Brauer, J. S. Apte, D. K. Henze, L. Zhang, Q. Zhang, B. Ford, J. R. Pierce, and R. V. Martin. (2022). NASA Socioeconomic Data and Applications Center (SEDAC). DOI: https://doi.org/10.7927/fx80-4n39 For inquiries about this service, please contact ciesin.info@ciesin.columbia.edu. Publication References:Documentation for the Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD), 1998-2019, V4.GL.03. Hammer, M. S., A. van Donkelaar, C. Li, A. Lyapustin, A. M. Sayer, N. C. Hsu, R. C. Levy, M. J. Garay, O. V. Kalashnikova, R. A. Kahn, M. Brauer, J. S. Apte, D. K. Henze, L. Zhang, Q. Zhang, B. Ford, J. R. Pierce, and R. V. Martin. (2022). NASA Socioeconomic Data and Applications Center (SEDAC). DOI: https://doi.org/10.7927/thr9-xe64

This raster records PM2.5 exceedance based on TEMPO data for the United States. It is published by patrick_rea.

Ozone Overview and Intended UseOzone (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, total column ozone and its vertical distribution are monitored 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) 0-2 km 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 2 kilometers (km) above the Earth’s surface. Ozone Level 3 files provide trace gas information on a regular grid consisting of 0.04° x 0.04° 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 regridding 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) 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. These data will be added to this service once they are reprocessed.  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 0.04º longitude x 0.04º 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), viewing zenith angle (removing data retrieved at high viewing zenith angles), and effective cloud fraction (removing where clouds obscure the tropospheric column) variables. The applied filters remove pixels based on the following: solar_zenith_angle > 80 or viewing_zenith_angle > 80 or eff_cloud_fraction > 0.5.  Data Validation and Limitations of Use These data should be considered as beta products per the Provisional Product Maturity level defined in the TEMPO validation plan. The products are not optimized for operational use and anomalies may exist. Users should refrain from making conclusive public statements regarding science and applications of the TEMPO data products until the products are designated to be at the provisional validation status according to the validation plan. Users may consult the 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 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.