- It is a given, confinement has improved the air quality in Occitania as everywhere.
- According to the observatory, the air quality the nitrogen dioxide concentrations were more than halved in Toulouse or Montpellier.
- But pollution with fine particles is abnormally high, mainly because of the weather ... or gardening.
It is one of the few good sides of containment. After weeks of forced immobility, the scarcity of cars has had its effect and, as was to be expected, we are breathing better. In Occitania, the Regional Air Observatory (Atmo Occitanie) has just published a study which now has a month of hindsight and which illustrates this spectacular result. At least for nitrogen dioxide (NO2).
The drop is 61% along the main roads from Toulouse, 59% in Montpellier, or 56% in Nîmes. "But the concentration has also dropped far from the main axes, in the urban background," said Dominique Tilak, the director of the organization. General NO2 pollution decreased by 57% in Toulouse, 49% in Montpellier, 46% in Albi or even 35% in Castres, the disparities being "probably linked to travel habits before confinement".
But all the pollution has not been removed and in particular not that linked to the famous fine particles in air suspension, PM2 and PM5. Since the start of confinement, their concentration has been going up and down but mostly exceeds the average for the last three years.
Gardening has helped
So why this greater fine particle pollution? "This is pollution from multiple sources and more balanced," replies Dominique Tilak. The car is only the second cause with industrial activities, the first being residential heating and the third agriculture. ”
Fine particles are, for example, particularly dependent on the weather and the air masses which were particularly stable during the first two weeks of confinement, causing air in the Occitania to stagnate more "charged with secondary particles" coming from the East. or from northern Europe. In the third week, the arrival of a “Saharan” air laden with sand aggravated the situation. And then there are the effects of confinement itself. These boilers that we pushed more than usual because we were at home in March, these heaps of weeds and fresh clippings that were burned by the lucky ones who were able to furnish the weather while gardening.
"But we can say that if the road traffic had been normal, the situation would have been much worse", relativizes Dominique Tilak. Its teams are preparing with interest to observe the evolution of pollution during the deconfinement. A unique opportunity to observe the real impact of human activities.
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- Languedoc-Roussillon
- Montpellier
- Covid 19
- Coronavirus
- Toulouse
- Pollution
- Confinement
- Planet