StreamAIR is the C-CAPS real time Earth Observation (EO) Data and Forecasting System with integrates observation and modelling of atmospheric composition, air pollutants, essential climate variables and advanced meteorology.

StreamAIR-AQ is air quality/atmospheric composition forecasting and realtime data system designed to monitor, observe and forecast Air Pollution over Europe and is operated on a grid resolution of 25 km x 25 km with nesting capabilities down to 1 km x 1 km. The modelling component is based on WRF-CHEM.

The StreamAIR-AQ currently forecasts the main particulate and gaseous air pollutant (e.g. PM2.5, PM10, NO2, SO2 and O3. The next version will include speciation of PM by species and emissions sector.

We present the current European Air Quality Index https://airindex.eea.europa.eu and its five Index levels of Good, Fair, Moderate, Poor, and Very Poor (see table below for concentration levels associated with these indices).

We also air pollution forecasts in terms of concentrations and exceedances as classified by the WHO Air Quality Guidelines (AQG). The WHO AQG are a combination of exceedance above a concentration threshold and an exposure time.

For Particulate Matter (PM), the exposure time is 24 hours and the thresholds for exceedance are 25 and 50 for PM2.5 and PM10, For O3, exceedance occurs for 50ppb over an 8 hour period. NOx is 106 ppb for1 hour and SO2 7.6 ppb over a 1 hour period. Warnings are given if the hour average of a pollutant parameter approaches an AQI threshold and if it exceeds the threshold, or is predicted to exceed the threshold the next 24 hours. For this scenario, a transparent mask in the colour representing that particular parameter appears at the time the exceedance is forecast. If the threshold average concentration is exceed for the specified duration, a full colour mask is displayed.