UVC dose to inactivate SARS-COV-19

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https://www.uvdi.com/international/wp-content/uploads/2020/03/International-News-Release-Med-Mar2020_MKTFM-454-Rev-A.pdf

on page 3 it quotes a dose of 611 uJ/cm^2 for 90% inactivation of sars-cov-19. Influenza-A is ~3 times as high at 1935uJ/cm^2.

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The estimations in the video arrive at a radiation energy of 1,325mJ/cm^2 in the middle of the pipe, which is several orders of magnitude more then what seems to be required for 90% inactivation.

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Given that more then 90% of UVC gets reflected by the mirror sheeting in the pipe and thus the radiation intensity is higher and UVC dose for 90% inactivation of SARS-COV-19 virus is three times lower then assumed in the video, the effectiveness is most likely significantly better then 60% (as calculated in the video).

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better source for k value for sars-cov-19: https://pubmed.ncbi.nlm.nih.gov/32547908/ it quotes the 90% UVC dose to be 10,3mJ/cm^2.

Edit: it appears tht the value of 10.3mJ/cm^2 is not for 90% inactivation but for 99%. see comments below.

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https://www.tandfonline.com/doi/full/10.1080/02786820500428575
Inactivation of Virus Containing Aerosols by Ultraviolet Germicidal Irradiation.pdf

this is a paper from 2005, on inactivating germs with UVC, and gives a broader scientific overview. It says

For airborne viruses, the UVGI dose for 90% inactivation was 339–423μWsec/cm2 for ssRNA, 444–494μWsec/cm2 for ssDNA,662–863μWsec/cm2 for dsRNA, and 910–1196μWsec/cm2 for ds-DNA

Sars-CoV-19 is ssRNA, as I found in this paper
https://pubs.acs.org/doi/pdf/10.1021/acs.analchem.0c02060
acs.analchem.0c02060.pdf

SARS-CoV-2 is an enveloped positive sense single-strandedRNA (ssRNA) virus, which means that the viral capsid isenclosed within a lipid bilayer and that the viral genome, notits complementary sequence, encodes viral proteins.

That means that the 90% UVC dose quoted in the scientific paper is most likely meant to be a 99.9% dose. Looking at this paper https://www.nature.com/articles/s41598-020-67211-2.pdf
s41598-020-67211-2.pdf
that impression is underlined.

Low doses of 1.7 and 1.2 mJ/cm2 inactivated 99.9% of aerosolized coronavirus 229E and OC43, respectively.

the 90% dose is given here:

For the alpha coronavirus HCoV-229E, the inactiva-tion rate constant (susceptibility rate) was k= 4.1 cm2/mJ (95% confidence intervals (C.I.) 2.5–4.8) which corre-sponds to an inactivation cross-section (or the dose required to kill 90% of the exposed viruses) of D90= 0.56 mJ/cm2. Similarly, the susceptibility rate for the beta coronavirus HCoV-OC43 was k= 5.9 cm2/mJ (95% C.I. 3.8–7.1) which corresponds to an inactivation cross section of D90= 0.39 mJ/cm2.

Conveniently, this also gives the k-factor for both corona virus types of 4.1cm^2/mJ and 5.9cm^2/mJ.