Highly prized in recent years, and especially since the beginning of the pandemic, air purifiers are the new healthy tools for the home. Filtration by air filters, ionization, or UV treatment… How do they work and above all… are they really effective?
An increasing number of devices, to be placed in a room, promises to eliminate viruses and fine particles. But how do they work? They are designed according to two types of processes: filtration using high-efficiency air filters, called Hepa, and destruction by photocatalysis, ionization, or ultraviolet treatment. Often, manufacturers combine the methods, more or less expensive, which explains the price differences, which oscillate between 50 and 1,000 €.
“All these techniques are based on scientific principles,” admits Laurence Galsomiès, an air quality expert at Ademe (Ecological Transition Agency). Understand that convincing tests have been conducted in laboratories. For example, several studies report an efficiency of more than 99% for Hepa filters (classes H13 and H14) on Sars-CoV-2 virus particles. Results that rise to 100% on fine particles, according to NASA. However, “the performance and the absence of risks of these domestic appliances are not demonstrated in real conditions of use, regrets the expert. Some equipment can even release harmful compounds, especially as they have aged.”
There is, however, a guarantee of efficacy and safety, the European ETV (environmental technology verification) certification, but it is currently only awarded to one device for local authorities. In the meantime, to preserve indoor air quality, the priority is to reduce pollutant emissions – avoid aerosols, favor “green” household products… – and ventilate every day.