Paris metropolitan area is rather privileged by presenting a relatively flat relief, a low altitude (from 11 to 217 m) and a temperate climate under
oceanic influences mainly (rainy and windy conditions) and continental occasionally. This is in favour of the atmospheric pollutants dispersion and
leaching. However, this good situation is counterbalanced by a density of population and activities extremely high.
Paris alone with its agglomeration concentrate about 90% of the regional population on a little more than 20% of the region area. The emissions of pollutants are thus concentrated there. The metropolitan area is responsible for more than 75% of the regional NOx emissions (see density of NOx emissions below), for 70% of the hydrocarbons (volatile organic compounds, VOC) and for half of the particles. In short, the NOx emissions of the Ile-de-France region represents 10% of the national ones.
If we only take into account the capital, 20% of the regional population live in Paris on less than 1% of the territory. Indeed, Paris contributes to 12% of the regional emissions of hydrocarbons (volatile organic compounds, VOC), to 6% of the regional emissions of fine particles (PM10) and up to 11% of the nitrogen oxides emissions.
In Paris metropolitan area, the three principal sources of pollution are: transport, heating (households and business) and industry. Among them, road transport (cars, vehicles of delivery, two wheels motorized and heavy lorries) is by far the major problem : it is responsible for 53% of the nitrogen oxides emissions of the Paris agglomeration, 15% of the volatile organic compounds and 25% of the particles produced by an increasing fleet of diesel vehicles (see sources of pollutant in Paris metropolitan area below).
For a certain number of pollutants the situation has been really improved thanks regulation on gasoline (by removing leaded gozoline or decreasing its benzene content) and technological improvement the vehicles fleet (for instance for nitrogen dioxide and carbon monoxide through the use of catalytic converters and its generalization). Sulfur dioxyde is no longer an issue, its level being decreased by 20% within 50 years due to a decreased number of heavy industries in the region and to the emission decrease of industrial activities.
Despite those improvements, between 3 and 4 million of people are exposed to levels of pollution above the European regulations due to nitrogen dioxide (NO2) and particles (PM10) levels in the Paris agglomeration. Close from the traffic, NO2 levels are not only exceeding the limit value, around twice the air quality objective, but are also rather stable above it. Increases have even been monitored by some stations. Meanwhile the decrease observed for the background levels seems to have come to an end. This is a great challenge for the coming years, especially with the air quality objective becoming a limit value in 2010 (see NO2 map for 2009 enclosed). In Background conditions, ozone also remains an issue, as well as benzene on busy and congested roads. (carte NO2 fond + prox 2009).
Levels of pollution encountered in 2010 in Paris area (yearly mean of stations, in µg/m3)
||Road side situation
||Ambient situation (background)
According to the French Air Act (Loi sur l’air et l’utilisation rationnelle de l’énergie, 1996), information and monitoring ambiant air quality for
the whoe of the Ile-de-France region is undertaken by Airparif. Airparif, like all the other French air quality monitoring networks is a non profit
and independent organisation, agreed by the French ministry of the environment.
Airparif was started in 1979. The Air quality monitoring implemented relies on the complementary use of three tools:
All data and information produced by Airparif are placed at the disposal of the public on the web: www.airparif.asso.fr
- results 24 hours a day from about 50 measuring sites distributed on the whole Ile-de-France Region, 12 of them being located in Paris. The main pollutants permanently monitored are nitrogen oxides, particles and fine particles, black fumes, carbon monoxide, volatile organic compound, monocyclic aromatic hydrocarbons, toluene, benzene, polycyclic aromatic hydrocarbons, heavy metals (lead, nickel, arsenic, cadmium), sulphur dioxide and ozone. Additional pollutants are also followed on a regular basis (e.g. aldehydes) or through specific monitoring campaigns (dioxins, pesticides, soot...). The pollutants monitored evolves according to the regulation and to the development of knowledge on their health and environmental effects.
- an emission inventory and modelling tools used for forecasting the air pollution, draw pollution maps, evaluate the air quality along the 20 000 km
road network and test the efficiency of reduction measures foreseen or already implemented by the authorities.
- detailed monitoring campaigns relying on mobile laboratories and diffusion tubes used to validate the models and the stations location but also to investigate in great details specific areas or subject of interest (airports, train stations, Paris ring road...);