Pollutants and various sources

Pollutants in the atmosphere can be of natural origin (they are then emitted by vegetation, soil erosion, volcanoes, oceans, etc.) or of anthropogenic origin, that is to say that They are “emitted” by human activities. All sectors of human activity are likely to emit atmospheric pollutants: industrial activities, waste treatment and construction sites, transport (road, air, river), domestic activities (heating in particular), agriculture or even forestry.
 

In the atmosphere, the pollutants observed are those emitted directly by these sources but also those which result from physico-chemical reactions between chemical components (primary pollutants and other constituents of the atmosphere) governed by meteorological conditions.

 

Census of pollutants source by source

The sources of pollutants, their geographic distribution, and the quantities of pollutants emitted can vary significantly depending on the time of year, or even the time of day. To identify them and better understand them, Airparif carries out an emissions inventory, for atmospheric pollutants and for the main greenhouse gases. This inventory makes it possible to identify:

  • The responsibility of the different sources,
  • The geographical distribution of emissions,
  • Their evolution over time.

The emissions inventory is a valuable tool for identifying the sources of pollutants on which actions would be most effective and for testing reduction scenarios that take these issues into account.
 

Air and climate

Airparif identifies emissions of atmospheric pollutants which have health effects and greenhouse gases which contribute to global warming. Note that, in ambient air, even at high concentration levels, CO2, the main greenhouse gas, is not associated with health impacts and is therefore not an air pollutant. Since activities emitting atmospheric pollutants generally also emit greenhouse gases, the levers for action to control these emissions are often the same. However, it is important to be vigilant, as certain actions have antagonistic effects between emissions of atmospheric pollutants and "climate" pollutants.


The main sources of pollution and greenhouse gas emissions in Île-de-France

The major sources of emissions, for atmospheric pollutants and greenhouse gases, are:

  • the residential sector (mainly heating),
  • road transport,
  •  depending on the local specificities of certain territories, activities such as industry, energy production, airport platforms, construction sites, agriculture, etc.

The residential sector (mainly heating) represents in 2019:

  • 9% of nitrogen oxide (NOx) emissions,
  • a third of particle emissions PM10 , more than half of the emissions of PM2.5, (of which more than 85% due to wood heating),
  • a third of non-methane volatile organic compound (NMVOC) emissions,
  • 30% of direct and indirect greenhouse gas emissions.

Road traffic represents in 2019:

  • half of nitrogen oxide emissions,
  • 16% of PM particle emissions10 and PM2.5,
  • 6% of non-methane volatile organic compound (NMVOC) emissions,
  • more than a third of direct greenhouse gas emissions,

Other sectors of activity contribute significantly to the emissions of certain pollutants:

  •  industry contributes 6% to nitrogen oxide emissions, 6% to PM particle emissions10, 22% to NMVOCs, and 8% to direct greenhouse gas emissions,
  • the energy sector contributes 4% to nitrogen oxide emissions, 31% to sulfur dioxide emissions and 8% to direct greenhouse gas emissions,
  • construction sites for 17% of PM emissions10, 12% of PM2.5, and 8% of NMVOCs,
  • airport platforms by 11% to nitrogen oxides and 9% to sulfur dioxide,
  • agriculture contributes 19% to PM emissions10 and 71% to emissions of ammonia (NH3), a precursor of secondary particles.

With the exception of agriculture, these sources generate greater emissions of atmospheric pollutants and greenhouse gases in the Paris metropolitan area given the density of its activities and habitat, but also along the major roads.

The density of pollutant emissions in the conurbation per km² is extremely high, compared to other regions, but the quantity emitted per inhabitant is, on the other hand, rather lower.