Coronavirus and UV-C

March 31, 2020

The COVID-19 pandemic is caused by the SARS-CoV-2 coronavirus, in the same group of viruses which caused the SARS epidemic in 2002-4 and the MERS outbreaks in 2015-18. A coronavirus is essentially a bit of RNA genetic material surrounded by a fatty membrane. Exposing it to hot water and soap dissolves the fatty membrane. Exposing it to UV-C radiation disrupts chemical bonds in the RNA. Both methods “kill” the virus, i.e. they make the virus incapable of hijacking living cells to make more of the virus. Information about UV and COVID-19 is available here: IUVA Fact Sheet With References.

The COVID-19 disease is not spread through treated drinking water supplies. Water from untreated sources can be made safe to drink using UV-C germicidal radiation. UV-C in appropriate doses is effective against viruses (including viruses in the Coronavirus group), bacteria, and microscopic parasites (including Giardia and Cryptosporidium). In all DayZero UV-H2O-Box products, exposure of clear water to the germicidal UV bulb for one minute delivers at least 40 mJ/cm2 of UV-C light energy throughout the tank, sufficient to reduce pathogens by 99.99% in the commonly used test protocol NSF P231. The report from the lab is available here.

UV-C radiation in air can also deactivate a coronavirus. To deal with a shortage of disposable masks during the COVID-19 pandemic, some medical organizations are using UV-C to decontaminate masks after use so that they can be used again (N95 Decon Process). Brian Crabtree has put instructions for building your own UV-C light box up on the Web at UVC Sterilizer for COVID-19 Emergency

The UV-H2O-Box is designed to disinfect water by shining UV-C light through it. If you leave out the water, it becomes a UV-C light box, capable of irradiating any object placed inside. Note that portions of any object shaded from the UV-C light do not get the germicidal effect of the light.