HEPA filters are key to keeping schools safe
Air purifiers in schools can reduce risk of COVID-19 infection by lowering concentrations of droplet aerosol particles carrying the virus. It allows direct intervention by using a highly efficient HEPA filtration system.
This is confirmed by research conducted in France using Camfil City M air purification units. These units have EN1822 tested HEPA filters fitted. (2 in each unit).
Researchers in laboratories that form part of the Lyonbiopole Infectiology Centre in Lyon, in southeast central France have conducted a €184,000 study into the efficiency of air purifiers used against the COVID-19 virus in schools.
Last December, 2,400 air cleaners were installed in almost 300 educational establishments, mainly in the canteens. (The risk of viral contamination is at its highest at mealtimes because that is when the masks come off).
According to politician Laurent Wauquiez, president of the?Regional?Council of?Auvergne-Rh?ne-Alpes: “This study tells us that the air purifiers do the job. It tells us that they can remove up to 99.9% of the COVID virus in a given space. And it also tells us that once the virus is trapped inside the air filtration unit, it doesn’t escape and dies after 48 hours.”
Mr Wauquiez is so confident of the results that he has asked the government to make the air purifiers widely available in high schools.
Another study, this time in Canada, and admittedly less scientific than the French research, has revealed that Quebec schools with air purifiers using HEPA filters reduce the COVID-19 infection rate by two to three times compared with schools without clean filtered air.
Since January 2021, most English public schools in the Montreal area of Canada have had air purifiers, air exchangers or some other form of extra air-quality device if they don't have built-in mechanical ventilation. French public schools in the same types of buildings have not had air purifiers.
Olivier Drouin, who runs the website Covid Ecoles Quebec, found that of 677 schools with confirmed COVID-19 cases since the beginning of January, 4,223 cases in total, an average of 6.8 cases per school. But in the 62 schools with purifiers, he only found 110 cases or an average of 1.8 cases per school, about a quarter of the broader rate.
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All of this is encouraging for the use of air purifiers. But beware – not all HEPA filters are created equal. It is essential that any filter specified must be properly referenced with its test standard and classification.
There are a lot of people hawking around so-called 'HEPA' filters in air purifiers that have no proper testing. That is not good enough if you want 99.995% efficiency for Maximum Penetrating Particle Size (MPPS) Classification H14. This is the classification used by laboratories for clean air to research into viral diseases such as COVID-19.
That is why it is essential for best protection that these HEPA filters are tested and comply with the recognized international European test standard BS EN1822:2019 with the appropriate classification.
To be truly effective against smaller (or ultrafine) airborne viral aerosol particles it is critical to specify the most efficient – an H14 class HEPA filter for use in a single pass standalone air cleaner or air purifier unit.
This international performance test standard, which defines minimum efficiencies for each filter class, is the gold standard when it comes to determining the efficacy of the HEPA particle removal air filters used in air purifiers.?
This clean air technology is now available for use in homes, schools, and healthcare settings.
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Well said Peter! The US has allowed for massive funding for schools to upgrade their air. Unfortunately, ionizers and "cheap as free", unproven filter systems have dominated, the money being used for other projects instead... gym renovations, additional staff, parking lot resurfacing, etc. With kids and teachers health at stake, covid or not, it's disappointing people still need convincing to do the right thing.