Why a real-time map?
Pollution levels vary throughout the day (morning and evening rush hours, middle of the night, etc.). They also vary from place to place. The air we breathe is different near road traffic, in a garden, from one side of a street to the other, etc. The maps inform you of the air quality to which you are exposed depending on where you are in Île-de-France.
They are updated every hour. This way you know your exposure level at any time of the day!
What do they represent?
The maps represent real-time pollution data for the region's problematic pollutants: nitrogen dioxide (NO2), particles (PM10 and PM2.5) and ozone (O3). A global index map summarizing the data on the concentrations of the pollutants cited above is also calculated.
How are they made?
This calculation chain uses the data produced by different models:
- ESMERALDA to describe concentration levels in background situations,
- Heaven to characterize pollutant emissions generated by road traffic,
- ADMS-Urban to describe the concentrations of pollutants generated by road traffic.
It takes into account the parameters influencing pollution levels, namely weather conditions, emissions of natural and anthropogenic pollutants emitted in the Île-de-France region, pollution produced in neighboring regions and countries and imported into the Ile-de-France region. .
The maps integrate the levels of pollutants measured in real time by Airparif monitoring stations spread across the entire Ile-de-France region. This so-called “assimilation” method makes it possible to improve the quality of maps by reducing the uncertainty linked to modeling techniques.
At what resolution?
These maps constitute outputs from digital tools capable of forecasting pollution in the coming hour. They offer a resolution of around 10 meters in Paris, 25 meters in the departments constituting the inner suburbs (92, 93, 94) and 50 meters in the outer suburbs (77, 78, 91 and 95), i.e.:
6 250 000 calculation points used to map the entire region
This system is in constant development. Ultimately, Airparif's objective is to distribute an hourly forecast map for the coming hours, while improving the quality of the results, the precision and the calculation times.
Disclaimer
It is important to note that these maps do not take into account specific events such as construction work, demonstrations, accidents, etc. that could modify vehicular traffic conditions as well as the concentration levels of pollutants on the roads concerned.
The index presented here differs from the daily ATMO index presented on the Forecast page, which is an overall exposure index in a background situation and which allows you to understand what you are exposed to on average over the entire day .
Monitoring of exceedances of hourly and daily regulatory thresholds at measuring stations
You can find the counter for thresholds exceedances by pollutant (hourly and daily) at the stations for the current year, not to be confused with the triggering of the information and alert procedure which are measured in relation to a criterion of surface area and population over the whole Île-de-France region.
- Download the file for the current year - PDF - approximately 25 KB per file (for nitrogen dioxide NO2, for ozone O3, for particles PM10 et for fine particles PM2,5 )
