About AirNow by Skymory

AirNow by Skymory: data sources and model estimates

An independent Skymory air-quality service. This is not the official U.S. AirNow service and is not affiliated with or endorsed by the U.S. EPA or AirNow.

The homepage app uses Open-Meteo CAMS atmospheric-model data and its model-derived U.S. AQI value. The 253 city pages use CAMS global atmospheric composition forecasts collected and processed by Skymory, with our own static pages and JSON. These are separate data paths.

City concentrations for PM2.5, PM10, O3, NO2, SO2 and CO come from the nearest validated point on an approximately 0.4-degree model grid. A city name identifies the selected area, not a sensor at your address. Values are regional model output, not street-level, monitoring-station or regulatory measurements.

What does the AQI estimate mean?

The city field is a CAMS model-based US AQI estimate. Pollutant concentrations derived from CAMS are compared with U.S. AQI breakpoint concepts using trailing samples from a single model run. Complete, partial and unavailable windows are shown explicitly. The window run can be older than the latest concentration forecast; its run and valid time are identified separately.

This informational estimate is not official EPA/AirNow reported AQI, a station observation, or the official operational monitoring/NowCast process. Official AQI is not supplied by this service. For official reports and health guidance, consult AirNow.gov or the appropriate local authority.

Times and updates

Model initialization is the start of a forecast run; valid time is the time represented by a sample. A page refresh or collection does not reset either. Checks are periodic and new forecasts depend on provider availability. Previous available data may be retained; a fresh label describes source age and coverage, not a measurement or accuracy guarantee.

Sources and license

Contains modified Copernicus Atmosphere Monitoring Service information 2026. City data: CAMS global atmospheric composition forecasts, supplied by ECMWF/CAMS under CC BY 4.0; Skymory performs city extraction and concentration conversion. Homepage data: Open-Meteo and CAMS. Provider attribution does not imply endorsement.

Health information is general guidance, not a diagnosis or individual safety assessment. Conditions at your location can differ. Skymory Weather city forecasts use MET Norway; one provider does not supply both services.

Reference points for some Korean cities draw on OpenStreetMap contributor data (ODbL).