UV and chemical sanitisation are only effective for a limited time (flash sanitisation) as they cannot be used in the presence of people on a continuous basis. Flash sanitisation’ with UV and chemical agents causes continuous sterilisation processes and subsequent recontamination, which promote an imbalance between beneficial and harmful bacteria (environmental dysbiosis). Ultraviolet rays are highly carcinogenic (link articles), cause severe skin and eye damage and produce large amounts of ozone (link articles). They do not permanently eliminate microbes but cause genetic damage that the microbes themselves are capable of repairing.
Temporary UV-induced sterilisation (link articles) by inactivating microbial colonies dispersed in the environment weakens our immune system, which needs continuous exposure to low, non-infectious doses of microbes in order to be efficient. Furthermore, both systems have a huge environmental impact because they are energy-intensive (UV) and release harmful substances into the environment (ozone for UV and various harmful substances for chemical disinfectants). The continued use of both also causes damage to surfaces and materials.