Paris (AFP)
Filter fine particles from urban pollution, pollen, dust or droplets of Covid suspended in a classroom or living room?
Air purifiers are the back-to-school attraction, but communities and consumers are having a hard time making their choice.
Catalysis, pulsed plasma, ozonation, electro-static filter, ionization, when it is not UV or activated carbon: faced with a jungle of techniques to filter the ambient air, no official quality label guarantees efficiency and safety of these devices.
The choice is most often dictated "by the marketing power", deplores Etienne de Vanssay, president of the Interprofessional Federation of Atmospheric Environment Trades (FIMEA).
"In Shanghai, China, almost everyone has an air purifier - or purifier - at home, in Europe we start from zero, but the market is developing and gaining momentum all over the world," he says. to AFP.
By 2030, the French air purifier market, between 80 and 100 million euros in 2020, could increase to 500 million euros, estimates FIMEA.
- "Huge" market, not too many standards -
At European level, sales, estimated at 500 million euros last year, should quadruple within ten years, while they would double on the planet, to 50 billion euros by 2030, adds the federation. .
A hospital in Barcelona equipped with an air purifier, May 14, 2020 LLUIS GENE AFP / Archives
The pandemic has played a revealing role for the need for air filtering: aerosols, invisible clouds of particles that we emit when speaking or breathing, are considered "the main route of transmission of Covid-19", recalls to AFP the epidemiologist Antoine Flahault, director of the Institute of Global Health at the University of Geneva.
After having slowed down for a long time, the Ministry of National Education recommends for this re-entry a "generalization" of carbon dioxide (CO2) sensors in the classes to measure the concentration of CO2 in the air and judge the need for ventilation.
For Mr. Flahault, air purifiers should be added "if the windows cannot open".
However, until the spring, the government slowed down on the equipment of communities by referring only to a negative opinion from ANSES dating from 2017.
Some technologies such as photocatalysis were then criticized for emitting titanium dioxide nanoparticles, or even for "sending back the virus".
The tone changed after the publication of an opinion from the National Research and Safety Institute (INRS), followed by another from the High Council of Public Health (HCSP) in April.
The two now believe that only purifiers equipped with a High Efficiency Air Particle (HEPA) filter are worthy of interest.
But the association for the prevention of atmospheric pollution (APPA) continues to put the brakes on mobile devices, accessible to the general public as well as to communities.
- Nothing replaces ventilation -
For the APPA, Dr Fabien Squinazi led a scientific report published in June recommending natural "aeration and ventilation" as "key principles" to ensure optimal air quality.
In short: open the windows for ten minutes every hour to bring in fresh outside air.
The association also points to the noise made by this equipment, which could interfere with the work of a class.
It remains to solve the problem of rooms not ventilated, or asthmatic students.
To get out of the imbroglio, the deputy Matthieu Orphelin called at the end of August for the establishment of an "action committee for an air quality strategy - Covid in schools" associating all the actors concerned (teachers, parents , directors, doctors, air quality experts, community representatives, etc.).
HEPA filter system at an airport in Indonesia, June 26, 2020 ADEK BERRY AFP / Archives
Some regions such as Auvergne-Rhône-Alpes and Ile-de-France have taken the lead in ordering purifiers with HEPA filters for their high schools.
On the industrial side, a reflection is underway to develop a "quality label".
About ten French FIMEA companies "are in the process of finalizing the experiments, we are awaiting the first results before the end of 2021" in order to inform consumers' choice "through technical and scientific information", indicates Mr. de Vanssay, who wishes to promote the concept of "potable air" (breathable): "Reprocessed air is more economical" according to him "than fresh air", the latter sometimes being "neither clean nor drinkable", especially near major traffic lanes.
© 2021 AFP