# CAMS Global Atmospheric Composition Forecast
*data products*

## Specifications
- **level**: L4
- **distributor**: ecmwf
- **access endpoint**: https://atmosphere.copernicus.eu/data
- **access model**: open
- **licence**: Copernicus open access
- **cost model summary**: Free and open via Atmosphere Data Store; 5-day global forecast including PM2.5, NO2, O3, SO2, CO
- **primary data portal url**: https://atmosphere.copernicus.eu/air-quality
- **deployment context**: ground
- **entity type**: data_product
- **last verified date**: 2026-05-31
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: ecmwf
- **attributes**: {"level":"L4","distributor":"ecmwf","access_endpoint":"https://atmosphere.copernicus.eu/data","access_model":"open","licence":"Copernicus open access","cost_model_summary":"Free and open via Atmosphere Data Store; 5-day global forecast including PM2.5, NO2, O3, SO2, CO","primary_data_portal_url":"https://atmosphere.copernicus.eu/air-quality","deployment_context":"ground"}

## Editorial
CAMS Global Atmospheric Composition Forecast is a Level-4 numerical weather prediction product from ECMWF, generated by the IFS-COMPO coupled atmospheric chemistry model. It covers more than 50 gas-phase species including O3, NO2, CO, SO2, PM2.5, and PM10, alongside seven aerosol types: desert dust, sea salt, organic matter, black carbon, sulphate, nitrate, and ammonium.[^ads-cams-forecast-overview]

The forecast runs twice daily at 00 UTC and 12 UTC, producing a 5-day horizon at 0.4 x 0.4 degree global resolution. Output is available at 1-hourly timesteps for single-level fields and 3-hourly timesteps for multi-level profiles. Files are delivered in GRIB format with an optional netCDF conversion. The archive extends from 2015 to present.[^ads-cams-forecast-overview]

This product is not satellite-derived. It assimilates satellite observations of atmospheric composition into a chemistry transport model, making it a model analysis and forecast product rather than a direct retrieval.[^ads-cams-forecast-overview]

Access is free and open via the Copernicus Atmosphere Data Store (ADS) at atmosphere.copernicus.eu. The model system is upgraded approximately annually; version changelogs are tracked in ADS release notes.[^atmosphere-cams-aq-page]

## Compositional position
- air-quality (topics) --[topic_capabilities]--> CAMS Global Atmospheric Composition Forecast
- ozone-stratosphere (topics) --[topic_capabilities]--> CAMS Global Atmospheric Composition Forecast

## Sources
- [ads-cams-forecast-overview] | CAMS global atmospheric composition forecasts - ADS overview | https://ads.atmosphere.copernicus.eu/datasets/cams-global-atmospheric-composition-forecasts?tab=overview | tier=operator-datasheet | accessed=2026-05-31
- [atmosphere-cams-aq-page] | CAMS air quality forecast portal, ECMWF | https://atmosphere.copernicus.eu/air-quality | tier=operator-marketing | accessed=2026-05-31

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Source: https://eo-atlas.org/data_products/cams-global-forecast
Maintainer: SpectraWorks B.V. (CC-BY 4.0)