In Germany, some schools have installed air purifiers to combat the spread of the SARS-CoV-2 coronavirus. On the other hand, France seems not to want to go in this direction, according to the Minister of National Education. Is this refusal really well founded?
In a German study published in October 2020, researchers ensure that the installation of air purifiers in classrooms can eliminate 90% of aerosols that the air contains. On November 2, 2020, France Inter gave the floor to Jean-Michel Blanquer, Minister of National Education. The person concerned was questioned in particular about the possibility of installing air purifiers in classrooms in France.
“We did a scientific study on these purifiers and it is absolutely not conclusive […] on the contrary, it even seems that sometimes it sends back the virus” , said the Minister.
If Jean-Michel Blanquer dismissed this possibility out of hand, he nevertheless insisted on the need to ventilate the rooms. Are air purifiers really useless? In response, the ministry refers to a study conducted by ANSES (PDF in French / 176 pages) in 2017. Nevertheless, the conclusions should be qualified because there is absolutely no question of uselessness regarding all purifiers.
The ANSES study effectively highlights the lack of efficacy (or even harmlessness) of certain plasma, ozonation or catalysis devices or photocatalysis. On the other hand, the most efficient air purifiers have the desired efficiency against the SARS-CoV-2 coronavirus. However, the fact is that these devices have high efficiency HEPA filters. In Germany, air purifiers in classrooms use precisely this type of filter. In addition, the local authorities have given even stricter ventilation instructions than in France.
The designation High Efficiency Particulate Air (HEPA) concerns filters that retain at least 99.97% particles with a diameter greater than or equal to 0.3 µm. This name is therefore a guarantee of efficiency. However, this only concerns filters that have successfully passed the Dispersed Oil Particulate (DOP) test, which measures the efficiency of the filtration of the famous particles. In addition, it is also a question of clearly differentiating between practice and theory . Indeed, these filters lose efficiency over time and require maintenance.
So why does France not want to acquire such air purifiers? Perhaps the ANSES study was misunderstood. Eventually, France would simply not want to do like Germany. However, be aware that HEPA-certified purifiers can cost several hundred, even several thousand euros . Indeed, equipping all the classrooms of the country would be a very expensive undertaking for the finances of the State.
