This article in our series about air purification technologies concerns photocatalysis-based air purifiers. Do they keep their promises?
The photocatalysis-based air purifiers innocuity called into question
Manufacturers most often use titanium dioxide (TiO 2 ) as catalyst. It is known to be effective against VOCs, gas, odors, mold, fungus, bacteria and viruses. According to the International Agency for Research on Cancer, titanium dioxide is also a carcinogen. Results from animal studies (ARC, DESK6 & Yamashita et al, 2011) indicate that titanium dioxide causes lung cancer and impedes fetal development.
Above all, degradation mechanisms involve dangerous by-products. It is difficult to guarantee that the photocatalytic reaction will be complete, as indicated in the picture. The factors listed can lead to a partial reaction and the emission of toxic by-products. Among them, ketones and aldehydes which have irritant and toxic properties.
For more information, click here and read an excellent French article by Corinne Mandin and Séverine Kirschner.