Anti-coronavirus containment has led to a sharp reduction in air pollution in France, in particular nitrogen dioxide, but less for fine particles, said Monday Ineris, the French Institute for the Industrial Environment and risks.
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49% less nitrogen dioxide on average in major French cities
"The concentrations of the main air pollutants have thus decreased in major French cities, in average proportions of 49% for nitrogen dioxide (NO²)", a local pollutant mainly emitted by road traffic, and from 10 to 12% for fine particles (PM 10 and PM 2.5), said the Institute in a press release. The lower impact on the level of particles is explained by the presence of emission sources not affected by confinement, residential heating, agriculture, or even natural dust.
To assess this "sharp reduction in air pollutant emissions, notably from road traffic and industry", Ineris based on a numerical simulation, integrating past data, and compared it to corrected simulations to integrate observation data from regional associations (approved by the State) for monitoring air quality in the country's 100 largest cities.
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A drop started ... before confinement
The decline actually began on March 12, five days before the start of confinement, "attributable to a first wave of measures, including the closure of schools and the encouragement of telework," notes the Institute. Conversely, from May 11, the end of deconfinement, "the two curves meet again, showing the immediate impact on the levels of nitrogen dioxide of the resumption of activities".
Airparif, which monitors air quality in Île-de-France, had already announced last week significant reductions in air pollution in the region during containment, with falls for nitrogen dioxide of 20 % to 35% depending on the week and up to 50% along the roads and 7% for particles. In addition to its harmful aspects for human health, air pollution is suspected of worsening sensitivity to the coronavirus.