Energy Dosage of Ultraviolet radiation (UV dose) in µWs/cm2 needed for kill factor

Irradiance is the power of exposure at the surface being disinfected. Irradiance is measured = µW-S/cm2 (micro-watt seconds) per square centimeter

Examples of a "Dose" (aka Kill Factor) for 99% elimination would have to deliver:
E. Coli - 6,600
Hepatitis - 8,000
Influenza - 6,600
Polio virus - 6,600
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Robots deployed in hospitals(Medical Grade) are disinfecting the 400-600 Sq. Ft. rooms and deliver a very HI irradiance in a short amount of time (e.g. 20sec to 20min) and you can't be in the room during operation. (Interesting fact - UVC doesn't pass through glass - so if there is a window looking into the room there is no risk of exposure.) The consumer products we're discussing don't deliver anywhere near that level of irradiation.

Example of measuring a dose:
You have a light 8 In above a surface. The Irradiance (Strength) being delivered would be much lower at the surface vs @ 1 cm from the source.

So now that we measure the strength at the surface, how long does the light need to be on to kill pathogens from that distance

Examples of a "Dose" (aka Kill Factor) needed for 99% (1 Log) elimination needed:
E. Coli - 6,600 µW-S/cm2
Hepatitis - 8,000 µW-S/cm2
Influenza - 6,600 µW-S/cm2
Poliovirus - 6,600 µW-S/cm2

If the light measured .175 mW at the surface and left it on for 60 Sec it would deliver a kill factor of 10,500 µW-S/cm2 effectively eliminating all of the above //

we know the dosage values for comparable viruses in the same SARS virus family are 10-20 mJ/cm2 using direct UVC light at a wavelength of 254nm; this dosage will achieve 99.9% disinfection (i.e., inactivation) under controlled lab conditions. In real-life, the virus is often hidden or shaded from direct UVC light, reducing UVC’s effectiveness. To compensate, researchers are applying dosages of 1,000 - 3,000 mJ/cm2 to ensure 99.9% deactivation, the current CDC disinfection goal (see CDC’s recently published guidelines, online - https://www.cdc.gov/coronav...