Photocatalysis air purifier: a solution or a threat?

Photocatalysis air purifier efficiency has not been proven

Most photocatalysis air purifier manufacturers assert that their air purifiers eliminate 99% of all VOCs, PAHs, viruses, and bacteria up to a size of 0,01 µm. There is an accumulation of research findings conducted in laboratories that confirm the depolluting properties of this technology. But tests under real-life conditions call into question that efficiency. According to the ADEME, photocatalysis is efficient only under certain conditions. Experiments reveal performance gaps depending on mixtures of air pollutants and airflows.

Under real-life conditions, photocatalysis-based air purifiers' efficiency depends on a variety of factors :

• The environmental conditions : temperature and humidity
• The parameters of the lights: power, spectrum:(UV-A, UV-C)
• The nature of the photocatalyst
• The wear of the photocatalyst
• The number of passages of the air that has to be cleaned on the active surfaces
• The nature and the concentration of pollutants