Several European cities have implemented traffic restrictions and pollution alerts in recent days amid high levels of nitrogen dioxide (NO2).
The pollutant, emitted by traffic, heating and industry has accumulated during the recent warm spell.
The animation in the player above, shared with Euronews by the Copernicus Atmosphere Monitoring Service, shows the concentrations and circulation of NO2 forecast in Europe.
NO2 has a short life-span, of about 24 hours, which means it stays close to its source, according to Copernicus experts.
The current warm spell goes hand in hand with low wind speeds and no precipitation, which makes more difficult to disperse these pollutants.
An improvement is expected by Saturday, according to Copernicus Atmosphere Monitoring Service predictions.