UV against SARS

Joey Fox has an explainer

Ultraviolet Germicidal Irradiation (UVGI), also known as Germicidal Ultraviolet (GUV) simply refers to using UV light to inactivate microbes like viruses, bacteria or fungi. They will still be floating in the air or found on surfaces and you will still touch them, ingest them or inhale them, but they become harmless.

There are many different ways UV light can be used and it often causes confusion. To know whether the UV system you are using is extremely effective, okay, useless or harmful, you need to be able to recognize the different types.

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Of all the methods we have to clean the air with a long historical evidence base, upper room UV is the most effective.

Here’s a table summarizing the approaches